inch → millimetre
1 inch = 25.4 millimetres; 1 millimetre = 0.0394 inches.
inch to millimetre
1 in = 25.4 mm
inch → millimetre conversion table
| inch (in) | millimetre (mm) |
|---|---|
| 1 | 25.4 |
| 2 | 50.8 |
| 3 | 76.2 |
| 5 | 127 |
| 8 | 203.2 |
| 10 | 254 |
| 15 | 381 |
| 20 | 508 |
| 25 | 635 |
| 30 | 762 |
| 40 | 1,016 |
| 50 | 1,270 |
| 60 | 1,524 |
| 80 | 2,032 |
| 100 | 2,540 |
Formula and notes
1 inch = 25.4 millimetres; conversely, 1 millimetre = 0.0394 inches.
The converter uses the base unit method: inch has a factor of 0.0254 and millimetre has a factor of 0.001, so the target value = source value × (0.0254 ÷ 0.001).
Length and area converters use exact international definitions, so results are consistent across calculators.
Other length conversions
inch to millimetre FAQ
How do I convert millimetre to inch?
Multiply the value in millimetre by 0.0394 to get inch.
Is the conversion exact?
Yes. Every unit is defined by a fixed factor relative to the base unit, so the result is exact apart from rounding.