Instantly convert inches (in) to millimeters (mm). Bidirectional, accurate, and free.
To convert inches to millimeters, use the formula millimeters = inches × 25.4. For example, 2 inches equals 50.8 millimeters. Type any number into the calculator above and the result appears instantly — you can also type into the millimeters box to convert the other way.
| Inches | Millimeters |
|---|---|
| 1 in | 25.4 mm |
| 2 in | 50.8 mm |
| 3 in | 76.2 mm |
| 5 in | 127 mm |
| 10 in | 254 mm |
| 20 in | 508 mm |
| 50 in | 1,270 mm |
| 100 in | 2,540 mm |
There are 25.4 millimeters in one inch. To convert any value, apply the formula millimeters = inches × 25.4.
The formula is millimeters = inches × 25.4. Enter a value above and the result updates instantly in both directions.
Yes. It uses the exact internationally-defined conversion factor, so results match official standards to several decimal places.
Yes — the converter is bidirectional. Type in either box and the other updates automatically using the inverse formula.