Convert millimeters to inches instantly. Type a value below to see the result, or press Swap direction to convert inches back to millimeters. The tool uses the exact conversion factor, and a quick-reference table is below.
Inches
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Conversion formula
Inches = millimeters ÷ 25.4
One inch is 25.4 mm. For small sizes, 10 mm is about 0.39 inches, a little under 3/8 inch.
Quick reference table
| Millimeters (mm) | Inches (in) |
|---|---|
| 1 mm | 0.0393701 in |
| 2 mm | 0.0787402 in |
| 5 mm | 0.19685 in |
| 8 mm | 0.314961 in |
| 10 mm | 0.393701 in |
| 12 mm | 0.472441 in |
| 15 mm | 0.590551 in |
| 20 mm | 0.787402 in |
| 25.4 mm | 1 in |
| 50 mm | 1.9685 in |
Frequently asked questions
How do I convert millimeters to inches?
Inches = millimeters ÷ 25.4
How do I convert inches back to millimeters?
Use the reverse formula, or press Swap direction in the converter above. You can also use our reverse converter.
How many inches is 100 mm?
100 mm is about 3.94 inches.
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Conversions use standard factors. Check critical measurements.