# Convert 21 mm to in

So you want to convert 21 millimeters into inches? If you're in a rush and just need the answer, the calculator below is all you need. The answer is 0.82677165354331 inches.

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## How to convert millimeters to inches

We all use different units of measurement every day. Whether you're in a foreign country and need to convert the local imperial units to metric, or you're baking a cake and need to convert to a unit you are more familiar with.

Luckily, converting most units is very, very simple. In this case, all you need to know is that 1 mm is equal to 0.039370078740157 in.

Once you know what 1 mm is in inches, you can simply multiply 0.039370078740157 by the total millimeters you want to calculate.

So for our example here we have 21 millimeters. So all we do is multiply 21 by 0.039370078740157:

21 x 0.039370078740157 = 0.82677165354331

## What is the best conversion unit for 21 mm?

As an added little bonus conversion for you, we can also calculate the best unit of measurement for 21 mm.

What is the "best" unit of measurement? To keep it simple, let's say that the best unit of measure is the one that is the lowest possible without going below 1. The reason for this is that the lowest number generally makes it easier to understand the measurement.

For 21 mm the best unit of measurement is centimeters, and the amount is 2.1 cm.