Inches to Millimeters
1 Inch = 25.4 Millimeters
Common amounts:
About the inch to millimeter conversion
The inch (in) and the millimeter (mm) are both units of length. Convert between metric and imperial length units — millimeters, meters, kilometers, inches, feet, yards, miles and nautical miles.
To convert inches to millimeters, multiply by 25.4. To go back, multiply millimeters by 0.03937.
Reference table
| Inches | Millimeters |
|---|---|
| 1 in | 25.4 mm |
| 5 in | 127 mm |
| 10 in | 254 mm |
| 25 in | 635 mm |
| 50 in | 1,270 mm |
| 100 in | 2,540 mm |
Need the reverse conversion? Convert Millimeters to Inches.
Convert Inch to other length units
Frequently asked questions
- How many millimeters is 1 inch?
- 1 Inch equals 25.4 Millimeters. To go the other way, 1 Millimeter equals 0.03937 Inches.
- What's the formula to convert inches to millimeters?
- Multiply the number of inches by 25.4 to get millimeters. For example, 10 inches × 25.4 = 254 millimeters.
- Does this converter handle decimals and very large numbers?
- Yes. Type any real number, including decimals or values in the trillions. Math runs entirely in your browser — no server round-trip, no sign-up, and nothing to install.