MM to Inches Converter
Convert a measurement in millimeters to inches. Enter a value below, or use the chart for small sizes you'll meet on tools, fasteners and parts.
Formula: inches = mm ÷ 25.4
Common millimeters to inches conversions
| Millimeters | Inches |
|---|---|
| 1 mm | 0.0393701 in |
| 3 mm | 0.11811 in |
| 5 mm | 0.19685 in |
| 6 mm | 0.23622 in |
| 8 mm | 0.314961 in |
| 10 mm | 0.393701 in |
| 12 mm | 0.472441 in |
| 20 mm | 0.787402 in |
| 25.4 mm | 1 in |
| 50 mm | 1.9685 in |
Need the other direction? Convert inches to millimeters or use the full Unit Converter for length, weight, temperature, area, volume and speed.
Everything you enter is processed in your browser and isn't sent to our servers.
How to use mm to inches converter
- 1Enter a length in millimeters.
- 2The equivalent in inches appears instantly, as a decimal.
- 3Use the swap button to convert inches to millimeters instead.
- 4Copy the result, or look up a common size in the chart.
About this tool
An inch is defined as exactly 25.4 mm, so inches = mm ÷ 25.4. The result here is a decimal inch; to compare with fractional sizes, 1/8 in = 0.125, 1/4 in = 0.25, 3/8 in = 0.375 and 1/2 in = 0.5.
Example: a 10 mm socket is 0.394 in — just over 3/8 in (0.375), which is why metric and imperial tools aren't interchangeable. Millimeters are standard for engineering drawings, screws, rainfall and jewelry sizes almost everywhere, while US hardware and many DIY plans still use inches.
Frequently asked questions
1 mm is about 0.03937 inches.