Convert in to mm instantly — formula, worked examples and a conversion table of common values.
Convert inches (in) to millimetres (mm). Enter a value on either side and the other updates instantly — nothing is sent to a server.
One inch equals 25.4 mm. The table below lists the values people look up most often, and each one links to a page with the worked calculation.
mm = in × 25.4| Inch (in) | Millimetre (mm) |
|---|---|
| 0.1 | 2.54 |
| 0.5 | 12.7 |
| 1 | 25.4 |
| 2 | 50.8 |
| 3 | 76.2 |
| 5 | 127 |
| 10 | 254 |
| 15 | 381 |
| 20 | 508 |
| 25 | 635 |
| 50 | 1,270 |
| 75 | 1,905 |
| 100 | 2,540 |
| 250 | 6,350 |
| 500 | 12,700 |
| 1,000 | 25,400 |
1 inch = 25.4 mm.
10 in = 254 mm.
100 in = 2,540 mm.
Use the formula mm = in × 25.4. Or type any value into the converter above — it works in both directions.