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How to Measure a Nut for Socket Size: Complete Guide

Choosing a properly measured nut is not an easy task to do.

They all look so same when choosing one from the many similar sizes. Knowing the tricks of measuring nuts helps in this scenario.

How to measure a nut for socket size?

To measure a nut, you’ll need a measuring tool of course. Besides, there are different systems and conversions of measurement. You’ll have to apply all these things properly while measuring a nut. You’ll also need to deal with various fractions and decimal points.

The small portion above may not be able to describe the full process. But don’t worry; we’ve discussed everything in the article below. If you can spare some time, have a read!

Process of Measuring Nuts

We understand that measuring the nut can be tough for you. But it’s time to forget all your worries. We’re here to let you know how to measure a nut for socket size.

We’ve divided the steps for the imperial system and metric system separately for your convenience. We’ve also discussed measuring nut threads in short. Let’s get to know them one by one.

Imperial Measurement System

The imperial measurement system is mostly used in the UK. It is also used in other Commonwealth countries. Units like inches and feet are used here rather than millimeters, centimeters, or meters. Let’s get to know the steps of measuring nuts in imperial units.

Step 1: Setting The Calipers

Take a digital caliper and set the reading in inches. Make sure the nut to be measured is kept on a flat surface. After that, open the jaws of the caliper to fit the nut between the jaws.

Step 2: Fitting The Nut

In this step, close the jaws of the caliper again so that the nut fits tightly. Make sure that the jaws connect with the flat sides of the nut. This should be done on both sides.

Step 3: Measuring The Value

When the nut fits the jaws of the caliper, the caliper reading should show the measurement. The reading is shown on the display. Often the results in the display indicate decimal values.

But imperial sockets sometimes contain fractions of inches measurement. In that case, you’ll have to convert the decimal value equivalent to a fractional value.

This is how you’ll be able to measure nuts for your socket size having an imperial system.

Metric System

The metric system is the globally accepted measurement system now. This measurement system is used for many common home repairs.

Here measurements are done using units like a millimeter, centimeter, meter, gram, kilogram, Liters, etc. The steps for measuring nuts in the metric system are quite the same as the previous one. Let’s have a look at them.

Step 1: Setting The Tools

Just like the previous one, take a digital caliper and switch the reading to a millimeter. Keep the nut on a flat surface and open the jaws of the caliper.

After that, close the jaws and fit the flat side of the nut with the jaws.

Step 2: Measuring The Value

When you’re done fitting the nut within the jaws, the display will show readings. The readings indicate the measurement in millimeters.

Sockets having a metric system are sized using millimeters. So, it’s easier to determine a nut for the specific socket size.

For decimal values, the nearest larger size than the reading determines the size of nuts and sockets.

Thus you can measure the nuts for the metric system.

Here we can see that a digital caliper is needed to measure which is a sensitive instrument. If you need to buy precision and accuracy-controlled calipers, we’ve some suggestions:

Product 1
Product 2

We hope you’ll find your desired product here.

Measuring Nut Threads

While measuring nuts, identifying and counting threads of nuts is also important. Because there are a lot of threaded fittings. We’ve talked about this in two steps. The steps are as follows.

Step 1: Counting The Number of Threads

There are threads in the inside part of the nut. They are too small in size to count with your fingers. That’s why you can use a magnifying glass to see and a pin to count. Thus you can keep the track of the threads.

Step 2: Identifying Thread Type

After counting the threads, it will be easier to determine thread type. For this, you’ll have to measure the nut thickness first. Measure the perimeter of the outside and inside part of the nut. Then you’ll get the thickness of the nut.

If there are 16 threads per inch thickness, then it’s a coarse thread. And if there are 20 threads per inch thickness, then it’s a fine thread.

So, this is the whole process of measuring nuts for socket size. Hope you’ll be able to extract the information you need.


How to determine the correct type of bolts and nuts to use?

Answer: There are certain codes for determining the types of bolts and nuts. From the codes, the bolts and nuts are identified.

How to measure the sockets?

Answer: The sockets can be measured using digital calipers. It’s almost the same as measuring nuts.

Is a 10mm socket available?

Answer: Yes, a 10mm socket is available. It’s one of the most commonly used metric-sized sockets.


Nuts and sockets are pretty commonly used things in our regular life. Keeping that in mind, we tried to represent how to measure a nut for socket size. We kept it simple so that you can understand easily.

Safety is important, so maintain safety while doing the work. That’s all from us.

Have a great day!