Converter
Millimetres to Inches
1 mm is 0.0393701 in. Type any amount below and the answer follows as you type, on your device.
The answer follows what you type, rounded to six significant figures. Nothing is sent anywhere.
The formula
in = mm × 0.0393701
Multiply the millimetre figure by 0.0393701.
Worked example
How many inches are in 10 millimetres?
10 mm → 0.393701 in
Multiply 10 by 0.0393701. The answer is 0.393701 in.
Quick reference
The common values, rounded to six significant figures.
| millimetres (mm) | inches (in) |
|---|---|
| 1 | 0.0393701 |
| 5 | 0.19685 |
| 10 | 0.393701 |
| 25 | 0.984252 |
| 50 | 1.9685 |
| 100 | 3.93701 |
| 1,000 | 39.3701 |
When you need this
Rainfall, timber thickness, bolts and camera sensors are quoted in millimetres here and in inches elsewhere, usually at a precision where the decimals matter.
The factor above is the exact legal definition of each unit, not a rounded one, so the answers stay right at any size. Nothing here is sent to a server: the conversion runs in the page.