Millimetres to Inches Converter
1 millimetre = 0.0393701 inches.
Enter a value
Result
1 millimetre =
0.0393701 in
1 mm × 0.0393701 = 0.0393701 in
1 inch = 2.54 cm exactly · 1 mile = 1.609344 km exactly
The working
- 1. Convert 1 mm to metres: 1 × 0.001 = 0.001.
- 2. Convert to in: 0.001 ÷ 0.0254 = 0.0393701.
1 mm in every unit
Handy reference lengths
- A4 sheet (long side)
- 29.7 cm
- Standard door height
- 2.03 m
- Football pitch
- 105 m
- Marathon
- 42.195 km
Conversion table
Millimetres to Inches
| Millimetres | Inches |
|---|---|
| 1 | 0.03937 |
| 2 | 0.07874 |
| 3 | 0.11811 |
| 4 | 0.15748 |
| 5 | 0.19685 |
| 6 | 0.23622 |
| 7 | 0.27559 |
| 8 | 0.31496 |
| 9 | 0.35433 |
| 10 | 0.3937 |
| 15 | 0.59055 |
| 20 | 0.7874 |
| 25 | 0.98425 |
| 50 | 1.9685 |
| 100 | 3.937 |
Inches to Millimetres
| Inches | Millimetres |
|---|---|
| 1 | 25.4 |
| 2 | 50.8 |
| 3 | 76.2 |
| 4 | 101.6 |
| 5 | 127 |
| 6 | 152.4 |
| 7 | 177.8 |
| 8 | 203.2 |
| 9 | 228.6 |
| 10 | 254 |
| 15 | 381 |
| 20 | 508 |
| 25 | 635 |
| 50 | 1,270 |
| 100 | 2,540 |
Formula and worked example
inches = millimetres × 0.03937007874 (1 inch is exactly 2.54 cm).
Convert 25 millimetres to inches: 25 × 0.039370079 = 0.984252 in.
When you need this
Engineering drawings, drill bits, bolts and camera lenses are specified in millimetres, while many tools and older parts in the US are in fractions of an inch. Rain gauges and jewellery sizes also switch between the two.
Questions people ask
How many inches are in a millimetre?
One millimetre is 0.039370079 inches. 1 inch is exactly 2.54 cm.
How do I convert millimetres to inches?
Multiply the number of millimetres by 0.039370079, or divide by 25.4.
What is 10 mm in in?
10 millimetres is 0.393701 inches.
How do I convert inches back to millimetres?
Multiply by 25.4: one inch is 25.4 millimetres.
Related conversions
How we calculate this
We use the standard published formula or definition for this calculation, and we show the working so you can check it. Source: NIST Special Publication 811, Guide for the Use of the International System of Units.
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