ACCURATE CONVERSION
Inches to Millimeters Converter
Convert inches (in) to millimeters (mm) with a standards-based formula.
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How to convert inches to millimeters
Enter a value in the converter above. The result updates immediately using the relationship below.
FORMULA1 inch = 25.4 millimeters
Inches to Millimeters conversion table
| Inches (in) | Millimeters (mm) |
|---|---|
| 1 | 25.4 |
| 5 | 127 |
| 10 | 254 |
| 20 | 508 |
| 50 | 1,270 |
| 100 | 2,540 |
Common values
For a quick estimate, multiply by the factor above. Use more decimal places when technical work requires additional precision.
Frequently asked questions
How many millimeters are in one inch?
One inch equals 25.4 millimeters.
How do you convert inches to millimeters?
Multiply the inch value by 25.4.
Can I convert millimeters back to inches?
Yes. One millimeter equals 0.03937008 inches; you can also use the swap button.