How to convert inches to millimeters
To convert inches to millimeters, use the formula mm = in × 25.4. In other words, multiply the number of inches by 25.4 to get the equivalent in millimeters. For example, 5 in equals 127 mm.
Inches to MM Converter
Convert inches to millimeters instantly. 5 in = 127 mm.
1 in = 25.4 mm
| Inches (in) | MM (mm) |
|---|---|
| 1 in | 25.4 mm |
| 2 in | 50.8 mm |
| 3 in | 76.2 mm |
| 4 in | 101.6 mm |
| 5 in | 127 mm |
| 6 in | 152.4 mm |
| 7 in | 177.8 mm |
| 8 in | 203.2 mm |
| 9 in | 228.6 mm |
| 10 in | 254 mm |
| 15 in | 381 mm |
| 20 in | 508 mm |
| 25 in | 635 mm |
| 30 in | 762 mm |
| 40 in | 1,016 mm |
| 50 in | 1,270 mm |
| 75 in | 1,905 mm |
| 100 in | 2,540 mm |
| 250 in | 6,350 mm |
| 500 in | 12,700 mm |
| 1,000 in | 25,400 mm |
Inch and Millimeter
The inch (in) and the millimeter (mm) are both units of length. This page gives you an instant, exact conversion between them, a reference table for the most common values, and the underlying formula so you can check the maths yourself. All calculations run in your browser — nothing you type is sent anywhere.
Need to go the other way? Use the MM to Inches converter. For all units at once, try the full Length Converter.
Frequently Asked Questions
How do I convert inches to millimeters?
Use the formula mm = in × 25.4. For example, 5 in equals 127 mm. Just enter your value in the converter above to get an instant result.
What is 1 inch in millimeters?
1 in = 25.4 mm. You can multiply any number of inches by this figure to convert it, or use the calculator above for exact results.
How do I convert millimeters back to inches?
Use the reverse conversion: 1 mm = 0.03937008 in. Our MM to Inches converter does this for you.