Best Digital Calipers – Buyer’s Guide & Reviews [2022]

A good set of digital calipers is an invaluable tool for any machinist or hobbyist. Calipers can take a wide range of measurements. 

And they do it with a lot of accuracy.

For many people, finding the best measuring caliper is important because they get used so much.

I used digital calipers almost every day for 15 years and there isn’t much competition. 

Mitutoyo digital calipers are the best. 

There is solid competition in the value department but Mitutoyo has the most well-made caliper on the market.

Name

Awards

IP Rating

Where to Buy

Mitutoyo 500-196-30 0-6" Digital Caliper

Best Overall Digital Caliper, Most Accurate, Easiest to Use

None

VINCA DCLA-0605 0-6" Digital Caliper

Best Budget Digital Caliper

None

Starrett 798A-6 0-6" Digital Caliper

Best Rugged Caliper

IP67

iGaging IP54 0-6" Digital Caliper

Best Budget Rugged Caliper

IP54

Mitutoyo 500-754-20 0-12" Digital Caliper

Best Large Range Digital Caliper

IP67

Mitutoyo 500-196-30 Digital Caliper

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Pros

Accuracy
Dependability
Battery life

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Cons

Cost

Accuracy: +/- 0.001”/.0254 mm

Measuring units: Inches, mm

Warranty length: One year

Battery used: 1 SR44 (included)

Amazing accuracy, excellent battery life and protection from dirt, water and oil. Mitutoyo makes a digital caliper that is everything you would want in a precision measuring tool.

These calipers from Mitutoyo are a reliable and consistently accurate measuring instrument. Perfect for reloading, engine work or every day use in a machine shop. 

Basically, Mitutoyo has set the standard for what a digital caliper should be and maintained that standard for a long time. In fact, if you can find a used set do be afraid to pick them up. 

These calipers are heirloom quality.

That isn’t something you would normally say about something electronic, but these digital calipers from Mitutoyo break the mold and are built to last.

Everything about these calipers is well-made.

  • Quality stainless steel frame
  • Solid plastic body
  • Buttons that just feel nice and are easy to use
  • Large, easy to read LCD display
  • Better battery life than any other caliper I have seen (Mitutoyo claims 3.5 years – it might be longer)

Combine these things with the dependable accuracy and you got a tool that is truly best in class.

VINCA DCLA-0605 Digital Caliper

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Pros

Price
Customer service

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Cons

No IP rating

Accuracy: +/- 0.001”/.0254 mm

Measuring units: Inches, mm, fractions

Warranty length: One year

Battery used: LR44 (included)

If you’re just getting into machining and you’re a bit nervous about dropping a lot of money on a high-end caliper like the one above, then this budget-friendly VINCA just might be the tool for you.

First and foremost, it’s a very accurate caliper for the price, with an accuracy of +/- 0.001″/.0254 mm. These are measuring devices after all. They need to be accurate.

While it is made of stainless steel, you’ll also be happy that this caliper comes with a heavy-duty case to keep it protected at all times when it’s not in use.

The LCD display face is fairly large, however you should note that the way the values are displayed is a little awkward, especially when measuring in inches. It appears VINCA did this to allow fractional measurements.

This isn’t something that is a deal breaker but worth noting because some of the numbers you will be reading are only half the size of the screen.

Battery life is good on these VINCA calipers. Take note that they automatically turn on when the caliper moves which can cause them to drain the battery faster even when not in use. Using the lock to gently keep them in place will go a long way towards extending your battery life and keeping them ready to use when you need them.

An excellent bonus feature of this caliper is the RS232 port which allows you to plug the caliper right into your computer. This is something that is rarely seen with budget priced calipers.

Digitally transferring readings can be super helpful, because it’s so easy to fat-finger a measurement if when entering them manually. 

Overall, these VINCA digital calipers are a great value for the price. They aren’t quite on the same level as some of the higher end measuring tools but they make an excellent starter set that doesn’t break the bank.

Starrett 798A-6 0-6″ Digital Caliper

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Pros

Protection from the elements
Accuracy

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Cons

Expensive

Accuracy: +/- 0.001”/.0254 mm

Measuring units: Inches, mm

Warranty length: One year

Battery used: CR 2032 3V (included)

It’s tough to do a review about calipers and not include anything made by Starrett. Starrett is an industry leader, and for decades has carried a solid reputation for making incredible products.

This heavy-duty digital caliper from them has an accuracy of 0.001″, or 0.254 mm and a resolution 0.0005″ or 0.010 mm. Exactly the type of precision you would expect in a quality measuring tool.

When it comes to build quality, the stainless steel bar of this caliper is designed to last just like many other Starrett tools and the case it comes with only helps to extend the life of your caliper by keeping it safe when you’re not using it.

This display is easy to read and quite large. The buttons work as designed and overall the 798A-6 functions exactly as intended and just feels very well built.

However, the real reason you’ll want to buy this caliper is because of how rugged this thing is.

The 798A-6 is rated IP67. IP stands for ingress protection. This is a measure of the amount of resistance a device has to dirt, water, and other contaminants. For a full breakdown of IP ratings, see our rundown in the Things to Consider section.

Just know that most digital calipers, especially lower priced models, often offer no IP rating at all. The better models that do offer some form of IP rating are usually rated IP54. The IP67 rating of this Starrett is a significant jump up in protection.

One thing to keep in mind is that the IP rating doesn’t protect against damage from drops or other physical damage. You’re going to still need to treat it carefully. But let’s face it, we aren’t always working in the most pristine environments.

While the added protection that the Starrett caliper offers is welcome, it does come at a cost. Mechanics and machinists have known for a long time the value of a tool that can withstand a little abuse. Whether that is necessary for you situation is something you will need to decide.

I can’t say that I know of anyone who has regretted spending the extra to step up and get a tool from Starrett.

iGaging IP54 0-6″ Digital Caliper

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Pros

Large display
IP54 rated

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Cons

No auto power off feature

Accuracy: +/- .001”/0.02mm

Measuring units: Inches, mm, fractions

Warranty length: Two years

Battery used: CR 2032 3V (included with spare)

While they are a budget tool manufacturer, iGaging has been around awhile and made quite a name for themselves providing decent tools for a much lower price.

Made of stainless steel, this iGaging caliper has an accuracy of +/- .001” or .02mm, and a resolution of .0005” or .01mm which is directly in line with the capabilities of higher priced tools. Fractional measurements are taken in increments of 1/128″

We tested the accuracy and it performed wonderfully reading spot on in all inside, outside and depth measurements taken across the measuring range. It even comes with a calibration certificate. Most budget priced tools skip this.

This is a solid set of calipers, especially for the price. The LCD display is large and skips the weirdness that other calipers such as the VINCA DCLA-0605 has because of the fractional units. 

igaging ip54 digital caliper display fractions

But the real standout feature of this caliper is just how tough it is given its price. The iGaging caliper has an IP54 rating, which, as we mentioned earlier, is the average rating for calipers with an IP score.

However, given the price point, this is a very uncommon feature for calipers in this price range. Most will have no IP rating at all.

Being a budget caliper, but still offering protection from dust, oil, water, and other contaminants is what sets this caliper apart from others in its class.

Another nice thing about this caliper is the 2-year warranty. You’ll notice that a lot of the calipers on this list are given a 1-year warranty which is still higher than the average warranty. 2 years provides quite a bit of assurance that the caliper will function for a good long time.

igaging ip54 digital caliper in box with battery

One small drawback of this caliper is that the on/off power function is manual. What this means is that you need to remember to hit the power  button every time you are done using it or else you’ll drain the battery. Many digital calipers will feature an auto off feature to extend the battery life.

Overall, the IP rating this tool has offsets any issues with battery life. iGaging has done a great job of making a budget priced tool that stacks up well in most areas against some of the most well known measuring tool manufacturers.

Mitutoyo 500-754-20 0-12″ Digital Caliper

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Pros

Large measuring range
IP67 rated

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Cons

Very expensive

Accuracy: +/- .0015”/0.0385mm.

Measuring units: Inches, mm

Warranty length: One year

Battery used: 1 SR44 (included)

We’ve included another Mitutoyo caliper on this list because this caliper is a bit different than the other one. For one, it’s got a much larger measuring range, going from 0-12″.

While measuring above 6″ is less likely, especially for beginners, this caliper gives you the option for larger measurements when needed.

Keep in mind that you wouldn’t want this as a replacement for a 6″ caliper, instead larger calipers such as a 12 or 24″ model will get used in addition to a 6″ caliper.

There are situations where you might need to measure something larger and the 6″ caliper just won’t do. But anytime you are measuring a smaller size, a large format caliper such as this will be difficult and awkward to use. Not to mention it won’t fit into tight spaces well.

You should also take not that the accuracy is slightly reduced because it needs to maintain that accuracy over a larger measuring range. This caliper has an accuracy of +/- .0015″/0.0385mm which is pretty good. 

You will find that some of the budget tool makers will spec their 12″ digital calipers with an accuracy of +/- .001″, which on paper looks like they are better than this Mitutoyo. In reality, they are often far worse than that. This is especially true if you move up to a 24″ caliper.

The Mitutoyo 500-754-20 comes with a whopping IP67 rating, meaning it’s super water and dust resistant. Having that level of protection on a tool that costs this much is important because you wouldn’t a splash of coolant or oil to destroy your prized measuring tool.

While it’s an expensive tool, if you have bigger projects that you plan on working with, then it’s well worth the money. And, as we touched on earlier, Mitutoyo is a premium brand in the industry, so if you do pull the trigger and decide to buy this caliper you won’t be disappointed in the quality of the product.

If you must go the budget route with a large range digital caliper, then be extremely aware of the accuracy you need and what the tool can actually provide. They might not line up.

I know everyone doesn’t have unlimited budgets so if you need to keep costs down, think about looking for a used Mitutoyo or Starrett digital caliper (good luck) or maybe going with a good quality dial caliper instead. Remember, that your large calipers are going to see much less use than a standard 6″ version.

All in all there are a lot of choices available nowadays when it comes to digital calipers and they are not created equal. 

Mitutoyo and Starrett lead the pack but they do come at a cost. 

Tools that have IP protection will help them last but may not always be a necessity for each user.

For smaller 6″ calipers, you can get a serviceable option that will often get the job done at a fraction of the cost. 

When it comes to larger calipers, don’t believe the claimed accuracy on those budget tools. 

Things to consider when purchasing a digital caliper

Accuracy vs resolution

Accuracy is the single most important feature of your digital caliper. 

They are measuring tools and they need to measure correctly.

The accuracy is the ability of the caliper to give the true value of a given measurement. The accuracy of the best calipers is usually +/- .001.

Cheaper alternatives will have an accuracy between +/- .002″ to +/- .010″. For some this may be fine, but it will depend on what level of accuracy you need for your project.

I also recommend that you do not blindly trust the claimed accuracies touted by the budget manufacturers. If Starrett or Mitutoyo specify an accuracy level, you can trust it but this is not the case 

Keep in mind the type of tolerances you will be working with to help you decide how accurate your caliper needs to be.

Measuring range

iGaging 0-24" Digital Caliper

The measuring range of the caliper is one of the most important aspects it has. You need to make sure that it will cover all the measurements you will want to take. 0-6″, 0-8″, 0-12″ and 0-24″ are some of the typical measuring ranges. 

0-6″ is the most common size of caliper. Measuring sizes over 6″ is less frequent. 

A 0-6″ caliper maintains a nice balance of measuring range and ease of measurement. As the measuring range of a caliper gets larger, it becomes more difficult to use. Using a 0-24″ caliper to measure a 1″ hole diameter would be quite difficult. 

Even if you require the ability to measure larger sizes, you will want a 0-6″ caliper for many measurements because of its ease of use.

Display size

mitutoyo digital caliper zeroed
Look For A Large Display

The display on your caliper plays an important role in how easy it is to use. Being able to quickly read your measurements will save you time in the long run. 

Let’s be real, some of us don’t have the best eyes. Larger displays make getting your reading simpler. This is one area that digital calipers have a nice advantage over dial calipers. The dial and indicator needle can be hard for some to read on your average dial caliper.

The best displays have large uniform digits as shown on the Mitutoyo caliper above.

Measuring units

Most digital displays are capable of showing measurements in inches as well as millimeters. Some calipers will also read measurements in fractional units. 

Fractional units are generally not the best way to take measurements because the displays don’t round and instead will display a measurement of something similar to 53/128″. That isn’t a very helpful way to display the data. If the display rounds to something useful such as 1/16 or 1/32 it would be more useful but most don’t.

Battery life

mitutoyo digital caliper sr44 battery
Typical digital caliper battery

Battery life should be a prime consideration when examining the quality of a digital caliper. An auto on and auto shut off feature can greatly extend the longevity of a calipers battery life. 

The best digital calipers will have battery life that is measured in months or years. Most of the budget options available have much shorter battery lives. If you go the budget route with your caliper, make sure to keep some extra batteries on hand and maybe think about taking the battery out when the tool is not in use.

The biggest benefit of good battery life is that it will be ready to use when you need it.

Dial vs digital calipers

dial caliper reading 0.661
Dial caliper face

Dial calipers make a good option for a measuring device as well. The main benefit they possess is that they don’t require batteries so they are always ready to use. 

Dial calipers can’t switch measuring units at the press of a button though. There are some dial calipers that measure in mm as well as inches at the same time but they haven’t been proven to be particularly reliable.

For a more comprehensive look at the two caliper types, be sure to check out our  guide to the differences between dial and digital calipers.

IP ratings

Ingress protection rating or IP rating for short is the amount of resistance a device has to things such as dirt and water. 

Many digital calipers have no protection rating at all.

For the ones that do, IP54 is the most common rating. This equates to limited protection from dust and protection from splashing water which will be more than most users require.

The less frequent IP67 rating is excellent and means they are almost impervious to everyday dirt and water.

Keep in mind though that IP ratings don’t protect the tool from physical damage such as being dropped.

The chart below outlines how protected a tool is. The first digit in any IP rating is for the solids protection and the second digit covers the protection from liquids.

ingress protection (IP) ratings solids description
ingress protection (IP) ratings liquid protection

Materials

Adoric digital caliper display
Carbon fiber digital caliper from Adoric

For most applications you will want to get a caliper made of stainless steel. Other materials available include carbon fiber composites and plastic. 

While tools made of carbon fiber and plastic are generally not as nice in quality as those made of stainless steel, they do have some benefits. Carbon fiber and plastic calipers are less likely to scratch or damage softer materials such as wood or plastic. 

Stainless steel calipers tend to have sharp jaws that can scratch some materials but if you are careful in their use, there shouldn’t be any issues. Carbon fiber composites and plastic also have the benefit of being non-magnetic.

Calibration certificates

Some calipers are sold with a calibration certificate for a decent upcharge. Skip it. The tool should be accurate when purchased, regardless of whether it comes with a certificate or not.

The best practice is to verify the accuracy of the caliper when you receive it. Check the tool against a known standard such as a set of gauge blocks. At a bare minimum, verify the zero position before using your gauge.

Cases

VINCA digital caliper in case unwrapped

A case is an important accessory for a digital caliper. These are precision measuring instruments after all and all too often they get knocked off a workbench or dropped by a careless coworker. 

Keeping them in a case will add a layer of protection to help keep them safe. Cases come standard with calipers from the the best toolmakers such as Starrett, Mitutoyo, Fowler and Brown and Sharpe. 

They do not come standard for cheaper tools so keep that in mind when looking at those budget friendly options.

Data transfer

An RS232 port can be a handy addition to your caliper, but is certainly not a necessity. A RS232 port allows the transfer of data/measurements from your caliper to your computer.

For most users this is an unneeded feature, but for some applications it can be handy to record the data directly to your computer.

How to Read A Dial Caliper [With Lots of Pics]

Reading a dial caliper doesn’t have to be difficult. 

There are two main parts to using a dial caliper: understanding the parts of the caliper and reading measurements from the tool

Parts of a dial caliper

It is going to be hard to use a dial caliper if you don’t know what the different parts of the caliper are called. 

Here is a quick run through for anyone who doesn’t already know the parts of a dial caliper.

a dial caliper with the different jaw measuring faces identified

The jaws of the caliper are the parts that will come in contact with your part when taking a measurement. 

There is one set for taking inside (internal) measurements and one set for taking outside (external) measurements.

the depth measuring rod of a caliper identified
the step measuring surface of a caliper identified

Most calipers can also take depth measurements with the depth measuring rod and step measurements using the back of the caliper.

the dial face of a dial caliper with the lock screw, dial face, dial bezel adjustment and thumb roller identified

Parts on the body of the caliper:

  • Dial face – Half of your measurement will be read from the dial. The other half will be from the scale on the beam of the caliper.
  • Lock screw – For locking the caliper in place. Measure, lock, read the measurement. Not needed with all measurements, but handy when working with parts that make reading your dial caliper difficult.
  • Bezel adjustment – Allows you to spin the dial face. For use when zeroing your caliper.
  • Thumb roller – Use this to apply an even amount of force when taking your measurement. 

The beam of the caliper is the part that the body/dial face slides along. 

The beam has a scale which is used to take half of the measurement. The scale reading gets added to the dial reading for your final measurement.

Steps to read a dial caliper

Now that we know what to call everything, let’s go through the steps to take a measurement with your dial caliper.

Step 1: Get ready to measure

Before you take a measurement with the dial caliper, make sure things are set up to allow you to get an accurate measurement.

You want:

  • A clean caliper. No dirt, dust, crud, rust, etc. 
  • A working caliper. Inspect for damage. Make sure the lock screw is loosened and the caliper body slides freely.
  • Good lighting. If you can’t see good, it will be hard to tell the difference between a 1.000″ and 1.001″. Proper lighting is your friend. 
example of trying to read a dial caliper in bad lighting conditions
Good luck taking this measurement

Step 2: Measure your part

Most dial calipers are capable of taking 4 types of measurements:

  • Inside
  • Outside
  • Depth
  • Step

Inside measurement

dial caliper taking a internal measurement

Outside measurement

dial caliper taking an external measurement

Depth measurement

dial caliper taking a depth measurement

Step measurement

Make sure your not taking measurements cock-eyed. If you have an angle on your part or your caliper, it can give you false readings.

With a little practice, it will be easy to get a feel for when your caliper is straight.

Step 3: Take a reading from the scale

a dial caliper with text that shows how to read the bar of the tool

The scale on the beam of the dial caliper has lines that mark the graduations. 

Most dial calipers will have them in increments of one hundred thousandths of an inch (0.100″).

You will take the reading of the last visible graduation. In the picture above, the line that would equal 3.100″ is not visible. This means that the the measurement is under 3.100″. Because the line isn’t visible, our reading from the scale would be 3.000″.

Step 4: Take a reading from the dial

The face of a dial caliper showing how to read the graduations on the diall

The dial face of most dial calipers has 100 graduations that each equal one thousandth of an inch (0.001″).

Simply count the number of lines. In the picture above, the dial reading is 0.027″.

Step 5: Add the scale and dial reading

Now you have your scale reading and your dial reading. All that is left is to add the two together. 

Let’s try another example. 

In the pic below, you can see that this time the 3.100″ graduation line is visible. This gives us a scale reading of 3.100″.

The needle of the dial is on the 6th graduation which equals 0.006″.

3.100″ + 0.006″ = 3.106″

a picture of a dial caliper with the instructions about how to read a measurement

Easy peasy lemon squeezy.

And if you still need more practice, check out the Dial Caliper Practice Quiz to make sure you have the process down.

Best Dial Calipers for Any Budget – Buyer’s Guide

It used to be that there were a limited number of options when it came to dial calipers.

Well known manufacturers such as Mitutoyo, Starrett and Fowler were the only choices available. Boy, have times changed.

Now the same tried and true tool makers are still there but they are competing from a long list of knock offs and up and coming manufacturers. 

Find out how the old compares to the new in our guide to the best dial calipers available found below.

Best dial calipers overview

Best overall dial caliper: Starrett 3202-6 0-6″ Dial Caliper

Best budget/starter dial caliper: Anytime Tools 0-6″ Dial Caliper

Best large range dial caliper: Starrett 3202-12 0-12″ Dial Caliper

Best budget large range dial caliper: Fowler 52-008-0 0-12″ Dial Caliper

Best made in America dial caliper: Starrett 120A-6 0-6″ Dial Caliper

Starrett 3202-6 0-6" Dial Caliper

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Pros

Exceptional accuracy
Built to last

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Cons

None

The Starrett name is synonymous with precision measuring instruments. Known for making quality micrometers and calipers as well as many other tools for well over a century. They are a premier machine tool manufacturer.

Their calipers are top shelf across the board. They have long been exceptionally accurate and well made.

Many of the features of Starrett’s caliper seem like simple things to get right. What makes this set of calipers better than all the others is the way that they are able to get all those little things right all at once and on a consistent basis.

As anyone who has used a set of calipers can attest to, the feel of a good set of calipers is where the tool shines. Starrett has been able to put it all together through the years and make calipers that provide top notch accuracy while maintaining an amazing level of smoothness in the mechanical workings.

Depth measurements are one area in which dial calipers from many manufacturers struggle. This is not the case with Starrett. Depth measurements from these calipers are every bit as accurate as any inside or outside measurement.

The accuracy is easier to attain with a tool as good as this one from Starrett. The thumb roller is smooth and with a little practice allows the user to gain a high level of precision in their measurements.

The easy-to-read dial face helps as well. The bright white face makes it easier to read your measurement even in lower light situations such as in your garage or leaning in to take readings in a dimly lit machine.

Overall, there are only positives for Starrett’s dial calipers. They just feel right and on top of it all are built to last. This truly is an heirloom quality tool.

Anytime Tools 0-6" Dial Caliper

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Pros

Price point
Customer service

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Cons

Not "shock proof"

Anytime Tools has quietly worked their way up to be one of the higher quality inspection tool makers. They have found a way to balance making a consistently good measurement device while still keeping the overall cost down. This is not an easy feat.

Easily the best budget friendly caliper. They have been able to create a tool that mirrors the same characteristics of calipers that cost almost twice as much.

As the best dial caliper under $50, it is amazing that they are still able to come packed with extras that other brands like to skip in an effort to keep the cost down. This caliper from Anytime Tools comes with a nice padded case that helps to keep the precision tool safe from accidental damage.

The dial face on this tool is one of the nicest. The lines are sharp and contrast nicely with the white background which makes reading the caliper easier.

The most important aspect is that they have been able to maintain the same accuracy of tools that cost almost twice as much. Nothing matters more than accuracy when it comes to inspection and measuring tools.

Starrett 3202-12 0-12" Dial Caliper

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Pros

The usual Starrett quality
Accuracy

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Cons

Hard to take smaller measurements
Cost

One thing you should know about any precision measuring tool such as a dial caliper is that as the measuring range goes up, the price can climb steeply.

You might think that the cost of a 0-12” caliper would be twice as much as a 0-6” set. Unfortunately, this isn’t the case and that 0-12” set can be 5-10x more expensive. This is especially true with sets from the most well-known manufacturers.

Luckily, Starrett makes a great 0-12” caliper that doesn’t completely break the bank. It has all the same great features of their 6-inch caliper but in a larger package. Another instance of a truly remarkable measuring tool. If you need a large caliper and trusted accuracy, then look no further.

One thing to keep in mind with larger calipers is that they will likely see much less use than a 0-6” set. Whenever possible you will want to use a smaller set of calipers for your measurements because they are so much easier to maneuver. It can be quite difficult to measure a small hole with a set of 12″ calipers.

Because they will be used less often, for some this may mean that they can sacrifice a little in accuracy and go with a cheaper set of 0-12” calipers. 

The Starrett 3202-12 is accurate to +/- 0.001″ which means it is an extremely capable measuring tool.

Just like any other measurement, you should pay attention to the tolerances you need before making any purchases.

Fowler 52-008-712-0 0-12" Dial Caliper

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Pros

Cost

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Cons

Reduced accuracy

There is only so much that can be said about any dial caliper. They are all constructed roughly the same. 

The biggest difference between any make or model dial caliper is the accuracy.

Most will want a caliper that is capable of taking measurements to +/- 0.001″ but if you know you can get away with a little less then there are some cheaper options available such as the 52-008-712-0 from Fowler.

Fowler has made/imported measuring tools for decades and done it well. Lately, they have skewed towards the lower end of the pricing range. Often they are not as cheap as the Chinese made tools and aren’t as accurate as the American, Japanese or European made tools.

Where they have really been successful is in making some of the tools that are more complex at a lower price point than most of their competition. Depth micrometers and dial calipers are two of the tools they have done well.

This dial caliper makes a great budget friendly choice for anyone who can sacrifice a little accuracy. Most will find this isn’t an issue because as parts get larger, they do tend to have looser tolerances. Pay attention though because this isn’t always the case.

 

Starrett 120A-6 0-6" Dial Caliper

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Pros

Excellent quality

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Cons

Cost

American made tools can be quite hard to come by nowadays.

Luckily, Starrett continues to make a selection of their tools in the USA. The only downside is that they come with an added cost.

At about double the cost, Starrett’s American made calipers are excellent but in my opinion they just don’t justify the cost. 

I realize that some would prefer to buy American made tools at all costs and because of this have include them on the list. 

This set of calipers is great. The build quality is amazing but it just isn’t enough to justify the added expense for most people. 

 

Things to consider when purchasing a set of dial calipers

Measuring range

Dial calipers come in a large variety of sizes. The most common size has a measuring range of 0-6”. Less common ranges of 0-4” and 0-8” are also available. 

Larger sized calipers such as 0-12” and 0-24” are available as well but they are most often used in conjunction with a 0-6” set of calipers. This is because taking smaller measurements with a large set of calipers can be extremely awkward. In most instances, the larger sets get pulled out when other measuring tools just won’t do.

Sets of calipers with measuring ranges above 24” are available but are much less common than sizes under 24”.

Accuracy

A good set of 0-6″ dial calipers is accurate to +/- .001”. Any 6 inch calipers which are less accurate should be ignored.

As the measuring range of the caliper gets larger, the accuracy of the caliper will often be reduced. Pay attention to the specs because it isn’t uncommon for a 24″ set of calipers to only be accurate to +/- 0.002″.

If you are in need of accuracy that is greater than this, you will need to find a nice set of micrometers for your application.

Micrometers are commonly available with an accuracy of +/- .0001”. Some cheaper sets of micrometers will not quite meet this accuracy, but you can rest assured that a set from the most well-known manufacturers such as Starrett and Mitutoyo will more than meet this standard.

Dial calipers sacrifice some accuracy to gain versatility in measurement.

Dial vs digital calipers

mitutoyo digital caliper measuring 1 inch block

Both dial and digital calipers have their advantages. For dial calipers, their lack of batteries mean they are always ready to take a measurement.

Digital calipers have the benefit of taking instant measurements as well as switching between units at the press of a button.

There is no difference between the accuracy of digital and dial calipers and they are both available with similar measuring ranges. Ultimately, the choice between which is better comes down to a matter of preference.

For a more complete guide to the differences between dial and digital calipers see our guide on the topic.

Micrometers vs calipers

starrett 0-1" micrometer

The differences between micrometers and calipers lie in their accuracy and versatility. Micrometers are more accurate but with a much smaller measuring range.

Micrometers are generally ten times more accurate than calipers and have a measuring range that is 1/6 of the range of a typical caliper.

For a complete rundown of the differences, see our full guide to the differences between micrometers and calipers.

New vs used dial calipers

Don’t be afraid to look for a good set of used calipers. Brands such as Starrett, Mitutoyo, Brown and Sharpe, and Fowler have made quality calipers for years.

This is especially true if you know where the tool is coming from. Often retiring machinists are more than willing to part with their tools if they know someone is entering the trade with a passion for it.

If you don’t know the history of the tools, make sure to check the accuracy before buying. Not everyone treats their tools as gentle as they should. If you have access, check any potential purchase against a known standard such as a calibrated set of gauge blocks.

One item to look for when purchasing used tools is a case. If someone has kept the case and/or original box for a number of years, then it is likely that they have treated it carefully and it is every bit as good as new.

What can a dial caliper be used to measure?

starrett 3202-6 6 inch dial caliper measuring a part

Dial calipers can be used for a large variety of measurements. Most models will take inside, outside, step and depth measurements.

The inside, outside and step measurements are fairly standard and will be consistent among many manufacturers, but the depth measurement is what sets many quality calipers apart from the pack.

Note: Some calipers with larger measuring ranges such as 0-24” will come without the ability to take depth measurements. This is true as well for outside measurements. Some calipers will come with the ability to only take outside measurements thought this is usually only for calipers with measuring ranges over 12”.

How to reset or zero a set of dial calipers

To adjust a dial caliper, move the caliper until the jaws are closed.

Once in the zero position, check your reading on the indicator needle. If it lines up on zero, then no adjustment is needed. You can proceed to verifying the tools repeatability as noted below.

If it does not line up on zero, loosen the bezel lock screw and turn the dial face until it lines up on zero. Once aligned, tighten the lock screw.

Now open and close the jaws to verify that the caliper repeatedly returns a zero reading.

Once this is verified, if available use a set of known reference standards such as a gauge block set to verify different readings across the calipers measuring range. For a 0-6” caliper, 0”, 2”, 4” and 6” would be a good start.

After the tool has been verified as accurate across its measuring range, you can proceed to take your part measurements.

How to calibrate dial calipers

gauge block set

Calipers should be calibrated periodically at an interval of your choosing. In a machine shop atmosphere, this will be determined by the company. Normal calibration intervals will range from 3 months to 1 year and everything in between. Some shops will even base the calibration frequency on tool use as opposed to length of time.

For home use, I recommend verifying them before each measurement.

With critical measurements, at home or in the shop, this verification becomes even more important. You don’t want to find out that your engine was bored oversize because you neglected to check your caliper before using it right?

Verify your tools and if possible, check them against a known calibrated standard such as a set of gauge blocks.

For more info on caliper calibration, please see our post on the Complete Guide to Caliper Calibration.

Calibration certificates

Please don’t pay more for anyone to provide a calibration certificate with your caliper. It just isn’t necessary.

Any extra money that would be spent on calibration costs would be much better spent on a set of gauge blocks so you can calibrate the tool yourself. Buying your own set of gauge blocks allows you to check the caliper regularly.

This can be especially important because it allows you to verify the accuracy of your measuring device, or measuring devices if you have more, right before taking a critical measurement so you know the readings are accurate.

Skip the calibration certs, if you think you might need it, get a set of gauge blocks and calibrate the tool yourself instead.

Maintenance and care tips

Lubricating your dial calipers

starrett tool and instrument oil bottle with cap
Starrett Tool and Instrument Oil

Most dial calipers will be made of stainless steel and therefore be resistant to rust. Not all types of stainless steel are created equal. Because of this it can be a good idea to have a light oil coating on some of the surface of the tool such as the beam.

Starrett makes a tool and instrument oil that works very well for lubricating all types of precision tools such as dial calipers.

Storage

It may be an old wives tale but many stand by not storing their calipers and micrometers with the measuring faces closed. Some say the surfaces in contact will corrode quicker. Others say it stresses the frame.

It is simple enough to back the tool off a little when you put it away and that is why we recommend doing it. If you plan to store the tool for extended periods of time, think about storing them with one of those little desiccant bags to absorb any rogue moisture.

Handle with care

Dial calipers are precision measuring tools, treat them like they are. They should be handled carefully and protected from shock damage as well as elements such as moisture and dirt.

Putting them away when not in use will go a long way towards keeping them out of harm’s way.

Cases

Dial calipers are precision measuring tools so the best thing you can do with them is protect them from damage as much as possible. Cases provide some damage from shocks and contaminants such as dirt, water, oil and/or coolant.

When not in use, the best place for quality measuring tools such as these is in a toolbox and the next best thing is in a decent case. Stash the case in your toolbox and you can double up the protection.

Depth base attachments

caliper depth base attachment

Calipers are notoriously difficult to use to take depth measurements. The nature of the tool makes it top heavy and therefore easy to get an incorrect reading when taking those depth measurements.

A depth base attachment makes the tool more stable and much more capable of taking accurate and repeatable measurements when it comes to things such as hole depths.

Dial caliper diagram and part names

parts of a caliper

Jaws

They are the primary measuring faces. They come into contact with your part. Make sure they are sitting square on your surface. You don’t want to twist the caliper at an angle because you won’t get an accurate reading.

Scale

The scale is used in conjunction with the dial indicator face to get your measurement reading. The scale reads in increments of .100” while the dial face reads in increments of .001”. They get added together to determine your measurement size.

Dial indicator face

Where you will look for the most important part of your measurements. The dial face reads in increments of .001”. The reading on the dial face gets added to the reading on the scale to get your measurement.

Beam

The beam is the surface along which the body of the caliper moves.

Depth rod

Not present on all calipers, though most have them especially at smaller sizes. The depth rod is the part of the caliper that extends out the end of the tool to take depth measurements.

Lock screw

Not present on all calipers, the lock screw allows the caliper to be locked in place to take readings that may be in hard-to-reach positions that may not allow the caliper to be read while measuring the part.

Related articles

Dial Caliper Reading Quiz

/10

Dial Caliper reading quiz

Test your ability to accurately read a dial caliper.

1 / 10

Enter the value for the measurement shown on the dial caliper above.

Values should be entered to the nearest thousandth of an inch (0.001”).

2 / 10

Enter the value for the measurement shown on the dial caliper above.

Values should be entered to the nearest thousandth of an inch (0.001”).

3 / 10

Enter the value for the measurement shown on the dial caliper above.

Values should be entered to the nearest thousandth of an inch (0.001”).

4 / 10

Enter the value for the measurement shown on the dial caliper above.

Values should be entered to the nearest thousandth of an inch (0.001”).

5 / 10

Enter the value for the measurement shown on the dial caliper above.

Values should be entered to the nearest thousandth of an inch (0.001”).

6 / 10

Enter the value for the measurement shown on the dial caliper above.

Values should be entered to the nearest thousandth of an inch (0.001”).

7 / 10

Enter the value for the measurement shown on the dial caliper above.

Values should be entered to the nearest thousandth of an inch (0.001”).

8 / 10

Enter the value for the measurement shown on the dial caliper above.

Values should be entered to the nearest thousandth of an inch (0.001”).

9 / 10

Enter the value for the measurement shown on the dial caliper above.

Values should be entered to the nearest thousandth of an inch (0.001”).

10 / 10

Enter the value for the measurement shown on the dial caliper above.

Values should be entered to the nearest thousandth of an inch (0.001”).

Your score is

The average score is 54%

0%

How to use a dial caliper

Before using your caliper, check to make sure that the measuring tool and surface to be measured are free of dirt, debris, chips, etc. The body of the caliper should slide freely along the scale or bar.

For an outside measurement, slide the jaws of the caliper open until they are far enough apart to be placed over the part to be measured.

parts of a caliper

Now proceed to close the jaws while trying to keep the jaws perpendicular to the surface being measured.

Multiple measurements should be taken to verify that the caliper has yielded the true reading.

For example, if a measurement is taken where the jaws of the caliper are not perpendicular to the surface being measured then the reading obtained can be larger than the true size.

Note: Do not use a large amount of force on the caliper in the direction of measurement. This can cause the tool to flex and give an incorrect reading. It is best to place the same amount of force that is used to zero the caliper.

How to read a dial caliper?

Reading a dial caliper is easy, though not as easy as a digital caliper.

Because costs have come down substantially in recent years, I recommend purchasing a digital caliper if possible.

If a digital caliper isn’t in the cards either because of budget or because you are working with an inherited tool then keep reading.

mitutoyo digital caliper display in inches
Typical digital caliper display

Dial calipers come in a few varieties, but most have their measurement read in the same way.

Dial calipers have graduations along the bar that are in increments of 0.1″ or one hundred thousandths of an inch. 

Often the 1,2,3, and so on whole inch increments are marked with a number and the 0.1″ increments will be marked with a line.

a dial caliper with text that shows how to read the bar of the tool

To read the caliper, combine the largest visible whole inch and 0.1″ increments on the beam with the dial reading. 

Your reading = Largest whole inch + largest 0.1 inch + dial reading

In the example below, the 3 inch graduation (line) is visible. So is the 0.1 inch graduation after the 3. 

If we add them together we get 3.1 inches. Now we need to add the dial reading to our beam reading.

The dial reading is 0.006 inches. 3.1″ + 0.006″ = 3.106″

The dial caliper measurement reading is 3.106″

a picture of a dial caliper with the instructions about how to read a measurement
A dial caliper with a measurement reading of 3.106"

How accurate are dial calipers?

A good set of 0-6″ dial calipers is accurate to +/- .001”. Any 6 inch calipers which are less accurate should be ignored.

As the measuring range of the caliper gets larger, the accuracy of the caliper will often be reduced. Pay attention to the specs because it isn’t uncommon for a 24″ set of calipers to only be accurate to +/- 0.002″.

If you are in need of accuracy that is greater than this, you will need to find a nice set of micrometers for your application.

Mitutoyo Micrometer

Micrometers are commonly available with an accuracy of +/- .0001”. Some cheaper sets of micrometers will not quite meet this accuracy, but you can rest assured that a set from the most well-known manufacturers such as Starrett and Mitutoyo will more than meet this standard.

Dial calipers sacrifice some accuracy to gain versatility in measurement.

Dial vs digital calipers

mitutoyo digital caliper measuring 1 inch block

Both dial and digital calipers have their advantages. For dial calipers, their lack of batteries mean they are always ready to take a measurement.

Digital calipers have the benefit of taking instant measurements as well as switching between units at the press of a button.

There is no difference between the accuracy of digital and dial calipers and they are both available with similar measuring ranges. Ultimately, the choice between which is better comes down to a matter of preference.

For a more complete guide to the differences between dial and digital calipers see our guide on the topic.

Micrometers and Calipers [Similarities, Differences & Everything Else]

micrometers vs calipers

Micrometers and calipers are both precision measuring tools.

The difference between these tools lies in their accuracy and the types of measurements they can take.

Check out the table below for the main differences between the two tools and then keep on reading to gain a better understanding of what those differences mean when it comes time to use them.

Micrometers

Calipers

Accuracy

0.0001"

0.001"

Measuring Range

1" increments

0-6"

Types of Measurements

Outside Measurements

Inside, Outside & Depth Measurements

Micrometer and caliper comparisons

Accuracy

Micrometers are more accurate. 

A typical micrometer is accurate to 0.0001″ and a caliper is only accurate to 0.001″.

This makes a micrometer 10x more accurate than a caliper.

Just keep in mind that you can buy cheap versions of both tools that have worse accuracy. Also, if you were to buy a larger versions of these tools they will often have lower accuracy. 

A 17-18″ micrometer might only be accurate to +/- 0.0002″ and a 0-24″ caliper may only be accurate to +/- 0.002″.

To sum it up, realize that there is some variation in accuracy but in general you will find that micrometers are 10x more accurate than calipers.

Measuring range

starrett micrometer set in case with reference standards

Micrometers come with 1″ measuring ranges. 0-1″, 1-2″, 2-3″ and so on. 

The most common measuring calipers measure over a 0-6″ range. Larger varieties can be also be found with 0-12″ and 0-24″ measuring ranges. There are some different ranges available such as 0-4″ and 0-8″ also but they are much less common.

This difference in measuring ranges means that you would need a set of micrometers to measure over the same measuring range a single caliper is capable of. 

Calipers have larger measuring ranges but they are less accurate.

Types of measurements they are capable of

Caliper measuring internal hole
caliper depth base attachment

Most calipers will measure inside, outside and depth measurements. 

digital caliper measuring coin
Standard outside diameter being measure with digital caliper

Micrometers are capable of only performing one type of measurement. 

The most common type of micrometer is an outside micrometer, usually referred to as simply micrometers or sometimes mics.

anytime tools 1-2" micrometer
0-1" outside micrometer

Inside micrometers and depth micrometers are also available to take internal and depth  measurements.

Calipers are capable of taking a much larger variety of measurements.

Depth micrometer with multiple rods for different size measurements
mitutoyo inside micrometer set
Inside micrometer with multiple attachements for different size measurements

Ease of use

To maintain the added accuracy that a micrometer has requires taking more care when using them. 

Something as small as the amount of force you use to close the micrometer can change your measurement. Many micrometers will have a ratchet or friction stops that help alleviate this problem. 

When you are working down to a tenth (machinist lingo for 0.0001″), even temperature comes into play. Metals expand and contract with changes in temperature. To protect against this, most micrometers have plastic pieces that can be used to help insulate your from the tool.

outside micrometer

A good micrometer stand can help keep you accurate as well.

The same factors affect the accuracy of a caliper but the effects aren’t as noticeable because they aren’t as accurate.

Speed

Calipers are quicker to use than micrometers. The jaws can open and close in a split second.

Micrometers need to spin the thimble around 40 times to cover an inch of travel. 

Cost comparison

A micrometer and a set of calipers have similar price points. Take for example a 0-1″ micrometer from Mitutoyo and a 0-6″ set of calipers from Mitutoyo.

The difference would be that to cover the same measuring range of a set of calipers, you would need a 0-6″ set of micrometers. A good set of micrometers is going to cost quite a bit more than your typical 0-6″ caliper.

More info about micrometers and calipers

Parts of a micrometer

parts of a micrometer

The part being measured will be placed between the anvil and spindle of the micrometer. The spindle is adjusted in and out by turning the thimble clockwise or counterclockwise. 

Depending on the micrometer being used, the lock nut, lock ring or lock lever can be used to hold the micrometer at a specific size. Some tools will not have any locking feature. 

Measurements are read using the scales on the sleeve and thimble. 

The frame of the micrometer can vary across brands and types of micrometers. Some are made specifically to have smaller frames for different measuring applications. 

Many micrometers also have a ratchet stop or friction stop that limits the amount of force applied to the thimble. This allows more consistent measurements.

Parts of a caliper

The jaws for external measurements are used to measure features such as length, width and thickness.

The jaws for internal measurement are used for measuring features such as hole sizes and slot or groove widths.

The rod for depth measurements is used for measuring depths of holes, counterbores and step heights. 

The scale and dial indicator face are used together to obtain measurement readings.

The slide of the caliper which consists of the moveable jaws along with the dial indicator face are slid along the beam.

The lock screw can be used to hold the caliper at a specific size for repetitive measurements.

Digital vs analog micrometers

Digital micrometers are great for the speed at which measurements can be read. Their display means very little training for the operator. 

Another benefit of a digital micrometer is how quickly measurement values can be converted between inch and metric readings. A simple button press can save time and do the conversion for you. 

starrett 0-1" micrometer
mitutoyo digital micrometer

The downfall is that they tend to be quite a bit more expensive than a standard analog micrometer and they are more susceptible to contaminants such as water and coolant. Some models are offered with resistance or protection from different contaminants. 

In recent years, prices have dropped for digital micrometers making them more affordable. 

Analog micrometers tend to be a very dependable tool and many have been in use for generations. This also means that there are many used options on the market for analog micrometers. 

If cost is your primary concern, I recommend going with an analog micrometer. If ease of use and operation is important then go with a digital micrometer.

Digital vs dial vs vernier calipers

mitutoyo 6 inch vernier caliper
Mitutoyo vernier caliper

Vernier calipers are the most resilient type of calipers. They will be the least affected by things such as dirt and water or coolant. Unfortunately they are the most difficult to take measurements with. Learning to read the scales takes some practice. 

Dial calipers are a good middle ground with measurements that are relatively easy to take with the dial indicator face. They are reasonably resistant to contamination though they should still be handled with care. 

anytime tools dial caliper dial face

Digital calipers are by far the easiest to use. The LCD display takes any guesswork out of reading your measurement. They are also the most susceptible to damage from things such as dirt and coolant. 

Unless they are being used in the harshest environment, I recommend getting digital calipers. Digital calipers can be purchased with ingress protection if needed.

Summary

While they are both precision measuring tools, there are some key differences between micrometers and calipers. 

Micrometers are more specialized and have a smaller measuring range. As a result they are generally more accurate and often capable of measurements to .0001″. 

Calipers are more versatile. They have a much larger measuring range. To achieve this they sacrifice accuracy and most often take measurements to an accuracy of .001″. 

As you can see they both have their strengths and weaknesses but in the end they are two of the most important precision measuring tools you can have in your toolbox.

Dial vs Digital Calipers – Which Is Better?

Somebody is going to get mad about this one. I just know it.

I have had many discussions with coworkers over the advantages and disadvantages of dial vs digital calipers.

What I have learned is that most people have a preference and that there isn’t anything that will change it. I am going to try and put aside any preference I have as I outline the differences between these two types of calipers.

Keep reading to find out more about the differences between digital and dial calipers. When you’re done, maybe you’ll have your own preference. But please, keep a more open mind than my coworkers.

What is a dial caliper?

A dial caliper is a mechanical inspection tool for measuring sizes accurately. Most models are capable of taking internal, external, step and depth measurements to an accuracy of +/- .001” or +/- .02mm.

The most common variety measures from 0-6” but they come in many different measuring ranges including 0-4”, 0-8”, 0-12” and 0-24”.

They can take quick measurements and are a very versatile inspection tool. For many machinists, a set of calipers will be the most frequently used measurement device.

The biggest differentiator for a dial caliper is the rack and pinion system which drives the indicator needle seen on the dial face.

Advantages

  • No batteries required
  • Tried and true design

Disadvantages

  • Can’t switch between inches and mm

What is a digital caliper?

mitutoyo digital caliper display in inches
Mitutoyo Digital Caliper

Digital calipers are the same sort of inspection tool as a dial caliper. They have similar accuracies and are available in comparable measuring ranges.

The main difference is that digital calipers require batteries which power their LCD display. The difference in displays between a dial and digital caliper can be thought of as the same as the difference between a standard analog clock and a digital version.

Advantages

  • Instant measurements
  • Can measure inches and mm

Disadvantages

  • Dead batteries
  • Electronics susceptible to damage

Are dial calipers more accurate than digital?

This can be a tricky question to answer because there are so many different models and manufacturers of both dial and digital calipers out there. In saying that, the short answer is no.

When comparing dial and digital calipers from the same manufacturer there is generally no difference in the accuracy of the tool.

Are digital calipers easier to use than dial calipers?

igaging ip54 digital caliper display mm
Digital Caliper Display - Notice the Button to Switch Between Units

Yes, digital calipers are easier to use than dial calipers. This is because the LCD display gives readings that can be instantly interpreted. Dial calipers require reading both the dial face as well as the scale to determine your measurement value.

Another added benefit of digital calipers that makes them easier to use is that most models are capable of switching between inches and mm at the push of a button. This saves the user from needing to convert measurements to another form of units.

This is an excellent feature for many users because it removes a step from the process which cuts down on the time needed to take a measurement. Removing the conversion step also eliminates the possibility that an error is made in the conversion calculation.

How to adjust or zero a dial caliper

parts of a caliper

To adjust a dial caliper, move the caliper until the jaws are closed.

Once in the zero position, check reading on the indicator needle. If it lines up on zero, then no adjustment is needed. You can proceed to verifying the tools repeatability as noted below.

If it does not line up on zero, loosen the bezel lock screw and turn the dial face until it lines up on zero. Once aligned, tighten the lock screw.

Now open and close the jaws to verify that the caliper repeatedly returns a zero reading.

Once this is verified, if available use a set of known reference standards such as a gauge block set to verify different readings across the calipers measuring range. For a 0-6” caliper, 0”, 2”, 4” and 6” would be a good start.

After the tool has been verified as accurate across its measuring range, you can proceed to take your part measurements.

How to adjust or zero a digital caliper

parts of adoric digital caliper

To adjust a digital caliper, move the caliper until the jaws are closed.

Once in the zero position, check reading on the digital display. If the display reads zero, then no adjustment is needed. You can proceed to verifying the tools repeatability as noted below.

If it does not read zero, press the zero button, sometimes identified as the origin button on some calipers.

Now open and close the jaws to verify that the caliper repeatedly returns a zero reading on its display.

Once this is verified, if available use a set of known reference standards such as a gauge block set to verify different readings across the calipers measuring range. For a 0-6” caliper, 0”, 2”, 4” and 6” would be a good start.

Once the tool has been verified as accurate, you can proceed to take your part measurements.

Things to consider when purchasing dial or digital calipers

Accuracy

Dial and digital calipers have comparable accuracies. There is some variation between makes and models of calipers, but most are accurate to +/- .001” or +/- .02mm. If you need something more accurate then you will likely need to look into purchasing a quality micrometer or micrometer set.

Most micrometers are accurate to +/- .0001” which makes them ten times more accurate than a typical caliper. The downfall is that they are more specialized and therefore are only capable of taking a single type of measurement (inside, outside, etc.) and have a smaller measuring range which is why a micrometer set is often needed to cover the measuring range of a single caliper.

Please note that cheap digital calipers often have reduced accuracy when compared to the usual gauge manufacturers such as Starrett and Mitutoyo. At the very least keep in mind the accuracy you need when purchasing because some of the budget priced tools are only half as accurate.

Measuring units

anytime tools 5 inch dial caliper with inch and metric reading dial
An Example of a Dual Unit Dial Caliper - Notice How It Has Two Indicator Needles

There are exceptions but most dial calipers are capable of measuring in a single set of units, either imperial (inches) or metric units (millimeters).

Some dial calipers are available that take measurements in both types of units, but they are clunky and often can not be calibrated so that both units are accurate. Stick with a single unit version.

Digital calipers are capable of taking measurements in both inches and millimeters while switching between the two at the push of a button. This is one of their primary advantages.

Many models are also able to take fractional measurements which can come in handy for some applications.

Measuring range

The measuring range of digital and dial calipers is similar. The most common version for both is a 6” caliper. Additionally, they can be found in ranges from 0-3” all the way up to 0-24” and beyond. Most will not find a need for measuring over 24”.

One point to keep in mind is that the cost goes up and the ease of use goes down as the caliper gets longer. For this reason, it is recommended to have multiple sets of calipers if you need to measure large sizes.

Imagine trying to measure a two-inch hole with a 0-24” caliper. It is going to be awkward and can easily lead to erroneous measurements. If you are in need of a set capable of measuring larger than six inches, then think about purchasing a quality 0-6” caliper as well as a 0-12” or 0-24” set.

The six-inch set will get the majority of the work and be easy to use and the larger set can be pulled out for use when the time is right.

Batteries

button cell battery for micrometer
Digital Caliper Battery Example

Dial calipers do not require batteries. This means they will always be ready to use, no matter how long they sit in your toolbox between uses.

Digital calipers on the other hand do require batteries and unfortunately not the types most people keep on hand.

Digital calipers typically use a LR44, SR44 or CR2032 battery. They are available at most department stores as well as online.

Modern digital calipers, especially the high-quality ones from Starrett and Mitutoyo, have extremely long battery life. Many people have reported going years between battery changes with a Mitutoyo digital caliper.

For peace of mind think about keeping an extra battery or two around in your toolbox or junk drawer if you decide to go with a digital caliper. This way it will always be ready to use when you need it.

Cases

VINCA digital caliper in case unwrapped
Digital Caliper with Case

Both dial and digital calipers are precision measuring instruments. You will find that most are built well and have no problem handling everyday use.

Unfortunately, the precision nature of these tools means that they are susceptible to damage from contamination such as coolant, oil, or metal chips as well as damage from physical shock.

A caliper that has been bumped off a workbench or dropped on accident can easily damage the jaws of the caliper or affect the internal workings resulting in invalid readings.

Calibration

gauge block set

Calipers should be calibrated periodically at an interval of your choosing. In a machine shop atmosphere, this will be determined by the company. Normal calibration intervals will range from 3 months to 1 year and everything in between. Some shops will even base the calibration frequency on tool use as opposed to length of time.

For home use, I recommend verifying them before each measurement.

With critical measurements, at home or in the shop, this verification becomes even more important. You don’t want to find out that your engine was bored oversize because you neglected to check your caliper before using it right?

Verify your tools and if possible check them against a known calibrated standard such as a set of gauge blocks.

For more info on caliper calibration, please see our post on the Complete Guide to Caliper Calibration.

Calibration certificates

Some of the caliper manufacturers and resellers offer a calibration certificate with their tool. My recommendation would be to skip this unnecessary add-on.

At a minimum you should be verifying your tool when you receive it. Ideally, you would calibrate the tool yourself with a set of calibrated gage blocks.

A calibration certificate will only serve as proof that the caliper was accurate at the time of calibration. Since many tools get ordered online or through a catalog, the tool will get be in a shipping company’s hand between the time of calibration and when you receive it. They aren’t always known for being gentle.

A calibration certificate doesn’t provide much peace of mind when buying a new tool. It should be accurate anyways, that is what you bought it for after all. It would be better to take the added expense of calibration and apply it towards a set of gauge blocks or other reference standard.

Depth base attachments

caliper depth base attachment

Depth measurements with a caliper can be quite tricky. The size and shape of the tool means it is top heavy and as a result it can be easy to get incorrect readings when taking depth measurements.

A depth caliper base attachment can help alleviate some of this by providing a wider, more stable base to take your measurements from. Adding one will make it easier to get consistent, accurate readings.

The base provides stability that is more in line with that of a depth micrometer, thought the tool will still be less accurate than a quality depth mic.

Related articles

Starrett vs Mitutoyo: Who is the Master of Measurement?

two calipers pitted against each other with text that says starrett vs mitutoyo

American precision measuring toolmaker, Starrett and her Japanese counterpart Mitutoyo are arguably the top players in the $25 billion measuring equipment market. Both companies boast rich production histories, and their tools are lauded for accuracy, dependability, and durability. 

Sure, there are dozens if not hundreds of measuring tool manufacturers but…

Let’s be real. These two are the best of the best.

We are going to take a look at the most popular measuring tools from both companies to find out how they stack up against each other. Spoiler! They both have their specialties.

But first let’s dive into a quick overview of the two companies because to many people, where the tools are made says more about the quality than any spec sheet ever could.

History of Starrett

Starrett tools factory building in 1905 on river with smokestack
Starrett factory in 1905

Starrett is old.

Like 140+ years old actually, but age is just a number right?

Well, with all those years Starrett has had plenty of time to perfect their tool making business. While we are going to focus on their measuring tools, they are also well-known for making about 5,000 other tools.

They make everything from precision measuring tools to saw blades, hand tools all the way up to fancy computerized inspection equipment. They make a lot of stuff and overall, they are known for making that stuff well.

While Starrett is headquartered in Athol, Massachusetts, USA, it operates several satellite facilities in different parts of the world including Mexico, Scotland, Brazil, and China. Some argue that those satellite facilities have made Starrett take a step down in quality but in general they have good quality control in place and their tools are still well-made.

History of Mitutoyo

outside of Mitutoyo corporate building

Mitutoyo, on the other hand, has yet to celebrate its first century in business. The company was established in Japan around 1934. Fast forward eight decades later, and Mitutoyo boasts a catalog of over 5,000 tools as well.

There tools are more focused on measuring related items and they make less hand tools than Starrett. Mitutoyo manufacturers the majority of their tools in Japan, however some tools are made in Brazil.

Enough history already, right? We’re here to talk about their most popular measuring tools. The kind every hobbyist or machinist is likely to be using.

Digital Calipers

The king of the calipers in my opinion. Digital calipers make for a versatile measuring tool that can take a large variety of measurements. Most are capable of measuring inside, outside, depth and step measurements with an accuracy of 0.001” or .02mm.

Remember that accuracy is the important feature to pay attention to with any measuring tool. Often manufacturers will try to list the resolution, which is the graduations that can be read with the tool. Just because you can read a measurement out to 0.0005” doesn’t mean the tool is accurate to that degree.

Now let’s look at the features of the digital calipers from both Starrett and Mitutoyo:

Starrett EC799A-6 Digital Caliper

Features:

  • Made of stainless steel
  • Measurement range of 6”/150mm
  • Has an accuracy of +/- 0.001”/0.02mm
  • Has a resolution of 0.0005”/0.01 mm
  • Large LCD display
  • Made in China

Take note that some Starrett calipers are made in the United States. The EC799A is made in China and still comes with a hefty price tag. To get a set made in America will likely set you back double.

We have included the EC799A because it is their standard digital caliper. If you Google “Starrett digital caliper”, the EC799A is what pops up. We have done the same with the Mitutoyo digital caliper as both companies make a wide range of calipers.

Mitutoyo 500-196-30 Digital Caliper

  • Made of hardened stainless steel
  • 5-year battery life
  • Measurement range of 6”/150mm
  • Has an accuracy of +/-0.001”/0.02mm
  • Resolution of 0.0005”/0.01mm
  • Large LCD display
  • Made in Japan

Best Digital Caliper

On paper, both tools have very similar stats. In use, the Mitutoyo digital caliper comes out on top with a better build quality, super-fast updating display and extremely long battery life.

Mitutoyo claims a 5-year battery life but unless you are using it all day every day, you can likely expect even longer.

Mitutoyo wins hands down.

Dial Calipers

Dial calipers are the digital calipers older, less tech savvy brother. What they lack in flash, they make up for in dependability. You’ll never pick them up only to find out that your battery is dead and you’re fresh out of button cell batteries in your junk drawer.

Dial calipers are capable of almost everything a digital caliper is with the exception of switching between units. A nice feature to have but not a necessity, especially when many people will find themselves always working in a single set of units.

Starrett 3202-6 Dial Caliper

Features:

  • Made of stainless steel
  • Has a range of 0-6 inches
  • Measures to an accuracy of +/- 0.001”
  • Has a resolution of 0.001”

Just like their digital calipers, Starrett makes a wide range of different dial calipers in various styles and measuring ranges. At the time of writing, they offer 34 different types of dial calipers with 26 made in the U.S and 8 manufactured overseas. 

Mitutoyo 505-742 Dial Caliper

Features:

  • Made of stainless steel
  • Has a range of 0-6 inches
  • Measures to an accuracy of +/- 0.001”
  • Has a resolution of 0.001”

Do those features look familiar? Yeah, they should. Copy. Paste. In fact you should expect the same of any dial caliper maker. They have been around long enough and almost because standardized. Unless you go with an ultra-cheap plastic caliper, you can expect similar specs from any 0-6” dial caliper.

Note: Mitutoyo has about 30 different types of dial calipers and all are currently made in Japan. 

Best Dial Caliper

On paper they are the same. Take a look at the pictures. They even have the same shape and same white dial face. In this case, I would give the edge to the Starrett dial caliper.

I think their action has always been consistently excellent, even on their Chinese made calipers. Also, the fine thumb roll adjustments are a little smoother, but it really is splitting hairs. The Mitutoyo is an excellent dial caliper too.

If you can find a good deal on one go for it but if the price is equal, I say go Starrett for your dial caliper.

Vernier Calipers

Vernier calipers are an interesting take on calipers. They don’t require batteries like digital calipers and they don’t have precision gear mechanisms that are susceptible to damage either. They are basically just two rulers that have their measurements read where the lines match up.

While these advantages would seem to make them the superior type of caliper, they do have some downfalls. For one they can be difficult for some people to read. Some people have trouble figuring out how to read the measurements while others have trouble visually reading them.

I say go digital for your calipers but it you must go old school, here is how Starrett and Mitutoyo stack up with their vernier calipers.

Starrett 125MEA-6/150 Vernier Caliper

Features:

  • Made of hardened stainless steel
  • 6”/150mm measuring range
  • Accuracy from 0-4” is +/- 0.001”
  • Accuracy from 4-6” is +/- 0.0015”

Mitutoyo 530-316 Vernier Caliper

Features:

  • Made of hardened stainless steel
  • 6”/150mm measuring range
  • Accuracy of +/- 0.002”

Best Vernier Caliper

Accuracy rules all when it comes to measuring tools and vernier calipers are no different. Starrett wins with double the accuracy and an included protective case as well.

I would still advise thinking about getting a set of digital calipers and maybe keeping some extra batteries on hand so you know they will be ready when you need them. Digital calipers are just infinitely faster and easier to read.

Standard Micrometers

Micrometers are made for checking extremely precise measurements. Many models are capable of checking tolerances of 0.0001” or better. That is 10x more accurate than a good caliper!

The downfall is what they gain in accuracy they lose in versatility. While a normal set of calipers can measure inside, outside and depth measurements from 0-6”, a micrometer will measure only one type of measurement and only over a 1-inch measuring range.

Starrett 436.1XRL-1 Standard Micrometer

Starrett’s micrometers are what they are most known for. They have been making them, and making them well for a very long time.

Features:

  • Narrow frame for measuring in tight spaces
  • Black enamel protective finish
  • Accuracy of +/- 0.0001”
  • Ratchet stop

Mitutoyo 103-177 Standard Micrometer

Features: 

  • Blue protective enamel finish
  • Accuracy of +/-0.0001”
  • Ratchet stop

Best Standard Micrometer

Once again, we see similar features from both manufacturers. This is to be expected as these are standard specs for a 0-1” micrometer.

One item to note is that the micrometers from both Starrett and Mitutoyo will be the same even as their sizes get larger. Expect a very similar product from both in their 5-6” micrometers and so on.

Even though they are similar, Starrett wins this category for multiple reasons. Their protective finish is nice and, in my experience, more durable. Their protective case is much more rugged, and their ratchet stop mechanism is smoother. That isn’t to say that the micrometer from Mitutoyo is bad, it just misses the mark compared to what Starrett produces.

Digital Micrometers

Digital mics are able to perform the same type of work as a standard micrometer. They add on an easy-to-read LCD display and depending on the model, they can allow the output of measurement data.

Often digital micrometers are the top tier tools and therefore have excellent accuracy, but they do tend to be a bit bulkier than a standard micrometer which can make them a little more awkward to use. Most won’t notice a huge difference but if you are planning to do a lot of one-handed measurements then you might want to stick with a lighter micrometer.

Best Digital Micrometer

I’m going to skip right to the chase and tell you that Mitutoyo hands down makes the best digital micrometers.

I don’t mean Starrett’s digital mics are bad, Mitutoyo is just that good.

They are extremely accurate and will measure down to +/- 0.00005”. That’s a lot of zeroes! Starrett’s digital micrometer is half as good. We know accuracy is huge when it comes to measurement, but the Mitutoyo’s also have a better ratchet stop to help get the most out of that accuracy whereas the Starrett mic has a friction thimble.

Personally, I have found friction thimbles to be slightly less accurate and not be as consistent over time (like 10 years, but still).

Lastly, the Mitutoyo digital mic has the same super long battery life as their digital calipers. Don’t plan on changing the battery or my mind anytime soon. Mitutoyo digital micrometers for the win!

Conclusion

Both Starrett and Mitutoyo make excellent measuring tools of all kinds. You honestly can’t go wrong with either one, but if you were paying attention then you may have noticed a pattern.

If you want the absolute best in category, then go with Starrett for your analog measuring tools and Mitutoyo for your digital options I guarantee you won’t be disappointed.

VINCA DCLA-0605 Digital Caliper Review

plus symbol

Pros

Great price
Has features not normally seen in its price range
Excellent customer service

minus symbol

Cons

Unusual display

Features

The VINCA DCLA-0605 0-6” digital caliper is nice little measuring tool. It is made of stainless steel and is capable of taking measurements in inches, metric and fractional units with an accuracy of +/- .001”.

The VINCA like many other calipers is able to take external, internal, step and depth measurements.

We tested those capabilities by measuring various size gauge blocks over the total measuring range of the tool and found them to be accurate to the manufacturers specs in all instances.

VINCA digital caliper display mm
Metric measurements
VINCA digital caliper display fractions
Fractional measurements

The DCLA-0605 comes with a large, easy to read display. One thing that does take some getting used to is that the first two digits are larger on the display. 

This allows the fractional units to be displayed. An odd choice when most will use the caliper in either inches or millimeters, but definitely not a deal breaker.

VINCA digital caliper display mm
Battery compartment shown

The VINCA caliper comes with an LR44 button cell battery installed along with  two spares. While the battery life isn’t as good as something like a Mitutoyo, it isn’t awful either. The caliper has an auto shut off feature for the display when not in use which helps it from draining all the juice.

The screen also flashes when the battery is low to let you know it’s time to swap batteries. Some digital calipers have been known to behave strangely when their batteries are low so this is a welcome feature.

VINCA digital caliper in case unwrapped

The DCLA-0605 comes with a protective case which is a nice bonus that some cheaper digital calipers don’t have. 

VINCA digital caliper data port
The RS232 data transfer port - DO NOT plug a USB cable in

Another feature not commonly seen on lower priced digital calipers is an RS232 port.

This will allow you to hook your caliper up to a computer to record measurements. It is worth noting that you should NEVER try to use a USB cable to hook the caliper up to a computer as this can cause the battery to explode. There are warnings all over the case and on the backside of the caliper to remind you.

Make sure to use the manufacturers recommended cable to connect your tool.

VINCA digital caliper rust on bar
Some rust on the frame

This VINCA caliper comes with a 1 year warranty and it is worth noting that by all accounts the company’s customer service is excellent. Considering my caliper arrived with some rust on the backside slot where the depth rod sits, that is probably a good thing. 

I am not planning on testing it for a budget level caliper, but they are noted as being quick to respond and offer solutions to any issues that are encountered. Maybe if there had been issues with the accuracy as a result.

VINCA digital caliper measuring 4 inch block
Accurate measurements across the board

The overall build quality of the tool is good. It isn’t the smoothest sliding caliper I have used but it does slide freely and it doesn’t catch or hang up at all. 

The fine adjustment wheel works well too and helps make those critical measurements as accurate as possible.

Verdict

VINCA digital caliper packaging
The packaging looks cool

The VINCA DCLA-0605 digital caliper is an excellent budget tool. It has accuracy on par with other calipers in its price range.

The addition of a nice protective case, a couple extra batteries and an RS232 port make it a great choice especially for those looking to record their measurements directly to their computer.

The 1 year warranty and noted excellent customer service make this VINCA caliper a great budget friendly digital caliper.

Beginners Guide to Micrometer Ratchets [Tips and Tricks for Use]

micrometer ratchets

Click, click, click. 

Is that the sound of a good measurement?

If you follow our guide to using your micrometer ratchet, then maybe. You can’t say we didn’t try.

Some of these tips might just surprise you. After all, it is all the little details coming together that let you get a good reading from your micrometer.

Check them out but remember that no amount of reading will beat some quality time practicing with your mic.

What is the ratchet on a micrometer used for?

Ratchets on a micrometer are used for consistency of measurement. The ratchet allows the micrometer user to apply a consistent amount of force to the tool resulting in more consistent measurements.

Micrometers are capable of taking measurements with a great deal of accuracy, most often to 0.0001” or 0.002mm. That is about 30 times smaller than a human hair.

The ratchet mechanism on a micrometer limits the amount of force that can be applied to applied to the tool.

Imagine taking a measurement with your micrometer by gently closing the tool on the part you are measuring. By doing this you get a measurement reading of 0.5000”.

Now with that same part you twist the thimble as hard as you can. Now the micrometer reads .4995”. Notice how the excess force has caused your reading to change.

 

Closing the micrometer quickly can have the same effect (too much force) and the ratchet mechanism will help in this situation as well.

Ratcheting mechanisms are especially helpful for anyone who is not used to working with a micrometer. The biggest thing to remember is that they aren’t perfect and there are many old micrometers out there with ratchets that don’t function properly.

Take multiple measurements and verify your tool to a known standard such as a calibrated gauge block to give yourself the best chance at an accurate measurement.

Will using a ratchet stop on your micrometer make your measurements more accurate?

This one is tricky.

No, using a ratchet stop will not immediately mean that your readings are more accurate. They can however make it easier to get accurate measurements.

If you are new to working with a micrometers we recommend you use the ratchet mechanism. But don’t assume this removes you from the equation. You should still do your best to be consistent in your measurements.

This means using a fairly gentle and above all consistent amount of force when using your micrometers. Spin it as fast as you want (within reason) until you are just about to contact the part you will measure. Improving the accuracy of your measurements happens in those last few thousandths of an inch.

yellow and black quick tips icon

Count your clicks

To improve your consistency, use the same amount of ratchet clicks when taking your measurements. We recommend starting with three clicks.

Ratchet or not, make sure to take multiple measurements to improve your skill using your micrometer. In fact, with enough practice, many people prefer to use their micrometer without the ratchet and instead relying on their “feel or touch” with the micrometer.

This isn’t beginner level stuff though, it will take some time and practice to develop the touch and even once you have gotten good with your tool, you should still be taking multiple measurements.

It only takes a spec of dust or lint, or a slight twist of your micrometer to give a measurement that is a few “thou” off. A few thousandths can often be the difference between perfect parts and scrap.

Ratchet stops vs friction thimbles

Ratchet stop
micrometer friction thimble example
Friction thimble

Ratchets aren’t the only type of mechanism used on micrometer to improve accuracy. Not only are there multiple types of ratchets with different levels of force, but there are also other options from different manufacturers such as friction thimbles.

With a friction thimble, once a certain amount of force has been applied the thimble will spin freely. No click, click, click.

Friction thimbles are still subject to the same issues as ratchet stops. They still require you to be consistent with the amount of force applied and it is best practice to take multiple measurements.

Friction thimbles, like ratchets, will lessen the effect that the micrometer user will have on their measurements, but they don’t eliminate that effect.

Tips for getting the most accurate measurements with your micrometers

The goal when using a micrometer is always to get the most accurate reading possible. To do this follow the tips below and give yourself the best shot at getting that measurement right on the money each and every time.

Keep it clean

contaminants that affect measurements

Your micrometer, your part, your workspace. Just keep everything clean.

Dirt, grime, lint, and oil are all enemies of accuracy. Clean everything with low lint wipes whenever possible. A quick visual inspection can help you determine whether your tool and part are free of contaminants.

Verify your micrometer

gauge block set

Whenever possible, check your tool at a size as close to the measurement size you are checking as feasible. If you are going to measure a 0.510” thickness, then grab a calibrated 0.500” gauge block and give it a quick check. This will provide some confidence that your tool is functioning correctly.

I always say that you never know what happened to your micrometer when you weren’t looking. Don’t think your kids or coworker wouldn’t knock it on the concrete floor, give a shifty glance around, put it back on your workbench and then walk away never saying a thing.

Right measurements are at right angles

a micrometer measuring a part at 90 degrees

You should be measuring your parts normal, or 90 degrees, to the surface being measured. What this means is that if you try to take a reading and your mic is cock-eyed, then you will get a bad measurement.

When at an angle other than 90 degrees, you will be measuring the hypotenuse of a triangle which will result in a larger than actual measurement.

This can largely be avoided by using a slight, gentle rocking of your micrometer when taking your measurements. With a little practice, you will feel the tool and part settle in and know that you aren’t getting a crooked measurement.

Be consistent

I covered it quite a bit earlier, but it is so important I want to touch on it again.

Consistency is king when it comes to measurement. Practice, practice, practice and you will develop that consistency. Some of it is just muscle memory so grab a known standard such as a gauge block or the standards that come with your mics to practice with. Measuring them over and over will allow you to develop that consistent form and force that will give you the most accurate readings possible.

Take multiple measurements

headline that says check, check and check again

Even the best machine shop inspectors can get a bad reading once. The tolerances are just too tight and the margin of error is too small.

A good inspector might get one bad reading, but you can bet that they won’t get three in a row.

Check your part multiple times to increase your confidence that you got a good reading. If you find that your measurements vary, then practice some more on a known size to work on your feel and form.

Check your tool again when finished measuring

Imagine you just finished taking multiple readings on a dozen parts with your micrometer. What should you do now?

Go check a gauge block! If you don’t have one, then at least check the zero of your micrometer. Too often something can happen to cause your measuring tool to be out of whack.

If you check the tool when you start and check it when you are done then you will only add to the confidence that all the measurements taken in between were accurate.

Safe storage

black plastic case for mitutoyo caliper
Many measuring tools come with plastic cases. Use them!

Take care of those precision measuring tools. If it came with a case, then put it back in the case and stash it in a desk, cabinet or somewhere else out of harms way.

Keep them away from those who would do harm to your precious instruments. I have never known anyone to have regretted putting their tools away and locking them up.

What can a micrometer measure? [Uses and comparisons]

a photo of someone holding a micrometer measuring a part with text that says what can a micrometer measure

Micrometers can measure a large variety of things, but they do have their limitations.

Those limitations are based on their accuracy and their measuring range as well as the type of micrometer.

Because they are specialized measuring tools, you need to make sure that you use micrometers for the right application and wouldn’t be better off with another measuring tool.

How accuracy affects what a micrometer can measure

Accuracy is one of the most important features of a micrometer.

Micrometers are commonly used to measure parts or features of a part, such as its thickness, to a high level of accuracy. Engine components are just one example of the types of highly accurate parts that micrometers are used to check.

Micrometers that read in inches are commonly accurate to +/- 0.0001” while metric micrometers usually measure to +/- 0.002mm.

There are some that do better and some that do worse, but in general most will measure with the above listed accuracy.

Because they are so accurate, they don’t work well for all measurements. For example, if you need to measure a board for a cut and you only need it accurate to 1/16 of an inch (which equals .0625”), then the micrometer is major overkill. It measures 625 times more accurate than you need!

They are slower too. If you only need accuracy of 1/16 of an inch, then bust out the tape measure, take your measurement and keep on trucking.

Micrometer measuring ranges

The other major limitation of a micrometer is its measuring range.

Inch micrometers measure in increments of 1”. So you will have a 0-1”, 0-2”, 0-3” micrometer and so on. This is why micrometers are often sold as a set with 0-3”, 0-6” and 0-12” sets being the most common.

starrett micrometer set in case with reference standards

Having a set of micrometers allows you to take accurate measurements over a larger range of sizes.

Metric micrometers are found in 25mm increments. 0-25mm, 25-50mm and so on. They too are sold as sets to cover larger measuring ranges.

Basically, a micrometer will take a very accurate measurement at the sacrifice of speed and the range of measurements it is capable of.

For many measuring devices you will find that as the accuracy of the tool gets better, the range it can measure over will get smaller.

Types of micrometers

Micrometers are also called screw gauges. There are many different types of micrometers that use the same screw gauge mechanism to measure different types of features. It’s doubtful you need to know about all of them so let’s stick to the basics.

Standard micrometer

outside micrometer
mitutoyo digital micrometer

First off is your standard micrometer. If someone simply says micrometer then they are referring to an outside micrometer or ‘mic’.

Outside mics are used to measure external dimensions such as the length, width, or thickness of a part.

They are by far the most common micrometer used.

Inside micrometer

mitutoyo inside micrometer set
Inside micrometer set

Inside micrometers get used to measure internal features such as hole diameters or slot widths. One thing to know about inside mics is that they are often not as accurate as outside micrometers.

The most common accuracy for an inside micrometer is +/- 0.001”.

Depth micrometer

depth micrometer
0-1" Depth micrometer

You are never going guess what a depth micrometer measures. Wait… you already know?!

Well thanks for ruining the surprise.

Depth mics measure the depth of features such as holes or slots. Just like an inside micrometer, they are often not as accurate as outside micrometers and usually measure to an accuracy of +/- 0.001”. Their design also means that they can be easier to get an incorrect measurement.

Practice using them on a known standard such as a gauge block is the best way to get good with them.

Accuracy vs resolution

We’ve talked a lot about the accuracy of micrometers, but we haven’t yet talked about their resolution.

Accuracy is how close to a true measurement the micrometer is capable of.

Resolution is how small the graduations that it can resolve are. At times the resolution of a micrometer, especially digital micrometers, may be better than the accuracy which can lead you to believe that you are measuring to tighter tolerances than you actually are.

When comparing micrometers make sure to pay attention to the accuracy of the tool.

Alternatives to micrometers

When it comes to picking a tool other than a micrometer to use, it all comes back to your accuracy needs and the speed of the measurement.

Let’s discuss the two main alternatives to micrometers:

Calipers

digital caliper measuring gauge block
Set of digital calipers measuring a gauge block

Calipers, whether digital, dial or vernier, are less accurate than micrometers. They typically measure to an accuracy of +/- 0.001”.

But what they sacrifice in accuracy they gain in versatility and speed of measurement.

While micrometers only measure a single type of measurement such as an outside, inside or depth measurement, most calipers will take all three.

They also have a larger measuring range with the most common type being able to take readings from 0-6”. You would need six separate micrometers to match the outside dimension measuring capability of a single set of calipers.

We discussed earlier how micrometers aren’t the fastest measuring tool to use. When compared to calipers this really becomes noticeable. A set of calipers could take dozens of measurements across their entire measuring range in the time it would take to take a few readings with a micrometer.

Calipers compared to micrometers have their advantages and their disadvantages. Pay attention to these differences when deciding which one is right for your measurement.

Dial indicators

dial indicator
Dial test indicator

Dial indicators come in a couple different varieties. First is the dial test indicator.

Dial test indicators are used to take comparison measurements. They get set up or “zeroed” to a known standard such as a stack of gauge blocks and measurements are taken relative to that standard.

A dial test indicator will have a relatively small measuring range, usually measured in thousandths of an inch (0.001”) and will measure to a high degree of accuracy such as 0.0001” or better.

They specialize in taking very accurate measurements repeatedly. If they are used to check a variety of measurements, then they will be quite slow to use because they need to be set up for each different measurement.

mahr drop indicator
Drop indicator

Another type of dial indicator is drop indicator. They most often come with a larger dial face, usually about 2-3” across, and they have larger measuring ranges.

A typical measuring range for a drop indicator is one inch but they do vary and can be smaller or larger. When compared to dial test indicators, they have significantly less accuracy. Most drop indicators are accurate to 0.001”. Their most common application is set up in either a snap gauge or a height stand which allows them to be used to take quick, repetitive measurements.