How many inches are in one millimeter?
One millimeter is 0.03937 in.
Millimeters to Inches
Type a value to convert it from millimeters to inches. One mm equals 0.03937 in.
Result
Millimeters and inches, side by side
One millimeter is 0.03937 in. In the other direction, one inch is 25.4 mm.
The factor is exact rather than rounded: imperial and US units have been defined from the metric ones since 1959, so the conversion introduces no error of its own. What you see below is arithmetic, not an approximation.
The millimeter is one thousandth of a meter, the unit of technical drawings and machine shops. Rainfall is measured in it, it is the smallest division on most rulers, and a credit card is about 0.76 mm thick.
The inch has been exactly 2.54 centimeters since the international yard and pound agreement of 1959. It survives worldwide in screen sizes, which measure the diagonal, in wheel rims and in pipe fittings, and in the United States for everyday lengths.
| Millimeter | Inch |
|---|---|
| 1 | 0.0393701 |
| 5 | 0.19685 |
| 10 | 0.393701 |
| 20 | 0.787402 |
| 50 | 1.9685 |
| 100 | 3.93701 |
Frequently asked questions
How do I convert inches back to millimeters?
One inch is 25.4 mm. The tool above converts in both directions.
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