Inches to millimeters
Type a value in either field to convert between inches and millimeters.
1 in = 25.4 mm
How to convert inches to millimeters
Multiply the value in inches by 25.4 to get millimeters.
Example: 10 in = 254 mm.
The inch is defined as exactly 25.4 millimeters (international agreement of 1959).
Frequently asked questions
How many millimeters are in a inch?
1 in equals 25.4 mm.
How to convert inches to millimeters
Multiply the value in inches by 25.4 to get millimeters.
Are these conversions exact?
Yes. They use the international definitions of each unit; results are rounded only for display.
| inches (in) | millimeters (mm) |
|---|---|
| 1 | 25.4 |
| 2 | 50.8 |
| 3 | 76.2 |
| 4 | 101.6 |
| 5 | 127 |
| 6 | 152.4 |
| 7 | 177.8 |
| 8 | 203.2 |
| 9 | 228.6 |
| 10 | 254 |
| 12 | 304.8 |
| 15 | 381 |
| 20 | 508 |
| 25 | 635 |
| 30 | 762 |
| 40 | 1,016 |
| 50 | 1,270 |
| 60 | 1,524 |
| 70 | 1,778 |
| 75 | 1,905 |
| 80 | 2,032 |
| 90 | 2,286 |
| 100 | 2,540 |
| 150 | 3,810 |
| 200 | 5,080 |
| 250 | 6,350 |
| 500 | 12,700 |
| 1,000 | 25,400 |
| in | mm |
|---|---|
| 1/64" | 0.396875 |
| 1/32" | 0.79375 |
| 1/16" | 1.5875 |
| 3/32" | 2.38125 |
| 1/8" | 3.175 |
| 5/32" | 3.96875 |
| 3/16" | 4.7625 |
| 1/4" | 6.35 |
| 5/16" | 7.9375 |
| 3/8" | 9.525 |
| 7/16" | 11.1125 |
| 1/2" | 12.7 |
| 9/16" | 14.2875 |
| 5/8" | 15.875 |
| 11/16" | 17.4625 |
| 3/4" | 19.05 |
| 13/16" | 20.6375 |
| 7/8" | 22.225 |
| 15/16" | 23.8125 |