1 millimetre = 0.039370079 inches
Millimetres to inches is the everyday conversion of the machine shop, where imported drawings and imperial tooling meet. One inch is exactly 25.4 mm.
Formula in = mm × 0.03937007874
Type in either field — the other updates on every keystroke. Need other units? Open the full length converter.
| Millimetre | Inch |
|---|---|
| 1 mm | 0.03937 in |
| 2 mm | 0.07874 in |
| 3 mm | 0.11811 in |
| 4 mm | 0.15748 in |
| 5 mm | 0.19685 in |
| 10 mm | 0.393701 in |
| 15 mm | 0.590551 in |
| 20 mm | 0.787402 in |
| 25 mm | 0.984252 in |
| 50 mm | 1.968504 in |
| 100 mm | 3.937008 in |
| 500 mm | 19.685039 in |
| 1000 mm | 39.370079 in |
| Inch | Millimetre |
|---|---|
| 1 in | 25.4 mm |
| 2 in | 50.8 mm |
| 3 in | 76.2 mm |
| 4 in | 101.6 mm |
| 5 in | 127 mm |
| 10 in | 254 mm |
| 15 in | 381 mm |
| 20 in | 508 mm |
| 25 in | 635 mm |
| 50 in | 1270 mm |
| 100 in | 2540 mm |
| 500 in | 12700 mm |
| 1000 in | 25400 mm |
| Situation | From | To |
|---|---|---|
| Pencil lead | 2 mm | 0.07874 in |
| Screw head | 10 mm | 0.3937 in |
| One inch | 25.4 mm | 1 in |
| Phone width | 70 mm | 2.756 in |
| Paper width | 210 mm | 8.268 in |
| A ruler | 300 mm | 11.81 in |
Divide by 25, which reads about 1.6% high. 50 mm is about 2 in.
Hardware, drawings, rainfall and screen glass use millimetres. 6 mm is 0.236 in, and 3 mm is about 1/8 in (0.118 in).
Do not treat 25 mm as exactly one inch in precision work: an inch is exactly 25.4 mm.
Since 1959 the inch has been defined as exactly 25.4 mm.
Related guides: Imperial vs metric: differences and quick conversion tricks