How to Read an Imperial Vernier Caliper in Inches: (3 Steps)

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In 1631 French mathematician Pierre Vernier invented a scale that can measure different dimensions and give an accurate result. This scale was named by his name as Vernier scale.

This scale become a common and useful tool among metal and woodworkers since its invention. Reading a Vernier caliper requires additional steps beyond those required for reading a dial or digital caliper.

Both scales require the users to manually calculate their results (the main scale and the Vernier scale). Our caliper experts explain how to read an imperial Vernier caliper.

How to Read an Imperial Vernier Caliper in Inches
How to Read an Imperial Vernier Caliper in Inches

How to Read an Imperial Vernier Caliper: Reading Vernier Caliper in Inches

The first thing that we have to do is determine the value of the smallest division on both the main scale and the Vernier scale. This is the opening phase. After that, we need to look into the zero error.

If the zero marking is not positioned in the correct position, we have a responsibility to take a reading of the value. The following step is to read both the main scale and the Vernier scale.

The final step is to combine the readings of the zero error scale, the Vernier scale, and the main scale. The conclusion of these three readings is what constitutes the final reading. Let’s go through each step one at a time.

Related: What are the Parts of a Vernier Caliper and Their Functions?

Guide to Reading Vernier Caliper in Inches (Imperial)

To read the Vernier caliper in inches experts break down the overall process into three steps. In those steps, they explain the reading process.

Step 1: Main scale reading

First, we have to take the main scale reading. In the imperial Vernier caliper, we will get the result in inches. The main scale is a total of 10 inches and the scale has a minimum reading of 0.025 inches for the smallest value that it can display (indicated by a single increment).

The number that is directed to the left of the 0 markers on the Vernier scale represents the value that can be found on the main scale. This particular instance has a value of 0.3 inches for this particular parameter.

As the zero is halfway between 0.3 and 0.325, we know that the distance between the jaws is somewhere between these two values.

Step 2: Vernier scale reading

Second, we have to check the value of the Vernier scale. Here we can see that an imperial caliper has a measuring range of 0.025 inches, and is graduated in 25 increments. Each increment represents 0.001 inch (a thousandth of an inch).

In order to interpret the Vernier scale, find the increment that corresponds most closely to an increase on the main scale. As the second component of your evaluation, this number is crucial.

In the above illustration, the intervals between each scale’s increments are identical, coming in at 13 thousandths of an inch (0.013).

Step 3: Calculate the total measurement

For the final total measurement, we have to add the main and Vernier scale readings. From the above we get,

Main scale reading= 0.3 &

Vernier scale reading= 0.013

Vernier error= 0

So the total measurement= (Main scale reading + Vernier scale reading)



So, the distance between the jaws of the Vernier caliper is 0.313 inches.

Related: Digital vs Dial vs Vernier Calipers: Which One is the Winner?


Learning to read a Vernier caliper entails reading a Vernier scale. Careful eye movement is required to determine which line is the straight one. If you only remember one thing about the Vernier caliper, let it be this. Good eyesight is necessary. Your measurement will be off if you skip that step.

To learn more about caliper you can check our other article. It will help to gather knowledge about calipers. Thank you and have a good day.


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Calvin Cameron

Hello, I'm Calvin Cameron. I'm a metalworking specialist for more than a decade. As a metalworker, I've been working in various areas like automotive plants, jewelry shops, and shipyards. I'm experienced with a lot of machines, tools, and materials. This is my loving area where I can talk and share about tools, measurement, and provide accurate data. Hope you will find some really good things from my research and studies. Enjoy reading.

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