🔄 Length Updated2026-07-19
Inches to Millimeters Converter.
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Quick answer
1 inch = 25.4 millimeters. To convert inches to millimeters, multiply by 25.4. So 10 in = 254 mm. The reverse: 1 millimeter = 0.03937 inches.
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Unit Converter
25.4
1 in = 25.4 mm
1 in = 25.4 mm · category base: metre
✨ Live · 6 categories, 45+ units. US customary volumes shown; UK/imperial gallons and cups differ.
🔢 Quick reference
Inches to Millimeters conversion table.
in → mm
| 1 in | 25.4 mm |
| 2 in | 50.8 mm |
| 3 in | 76.2 mm |
| 5 in | 127 mm |
| 10 in | 254 mm |
| 20 in | 508 mm |
| 25 in | 635 mm |
| 50 in | 1,270 mm |
| 100 in | 2,540 mm |
| 1,000 in | 25,400 mm |
mm → in
| 1 mm | 0.03937 in |
| 2 mm | 0.07874 in |
| 3 mm | 0.11811 in |
| 5 mm | 0.19685 in |
| 10 mm | 0.393701 in |
| 20 mm | 0.787402 in |
| 25 mm | 0.984252 in |
| 50 mm | 1.9685 in |
| 100 mm | 3.93701 in |
| 1,000 mm | 39.3701 in |
❓ FAQ
in to mm FAQ.
How many millimeters are in a inch?
One inch equals 25.4 millimeters. So to convert, multiply the number of inches by 25.4. For instance, 10 inches = 254 millimeters.
How do I convert inches to millimeters?
Multiply the inch value by 25.4. Worked example: 10 in × 25.4 = 254 mm. To go the other way, divide by 25.4 (or multiply by 0.03937).
How many inches are in a millimeter?
One millimeter = 0.03937 inches. Inches are typically used for screen sizes, and everyday lengths in the US and UK, and millimeters for small dimensions in engineering, screens and rainfall, so this reverse conversion comes up whenever you switch between the two systems.
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