How to convert inches to millimeters
One inch equals 25.4 millimeters, so multiply the value in inches by 25.4: mm = in × 25.4.
Example: 10 in = 10 × 25.4 = 254 mm.
Inches to millimeters table
| Inches (in) | Millimeters (mm) |
|---|---|
| 0.1 | 2.54 |
| 0.5 | 12.7 |
| 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 |
| 15 | 381 |
| 20 | 508 |
| 25 | 635 |
| 30 | 762 |
| 40 | 1,016 |
| 50 | 1,270 |
| 75 | 1,905 |
| 100 | 2,540 |
| 250 | 6,350 |
| 500 | 12,700 |
| 1,000 | 25,400 |
About the units
- Inch (in): Exactly 2.54 cm by international agreement (1959); used for screens, tools and US measurements.
- Millimeter (mm): One thousandth of a meter — the standard unit on engineering drawings and for screen sizes in specs.
Need the other direction? Convert millimeters to inches — 1 millimeter = 0.03937 inches.
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Open the unit converter Frequently asked questions
How many millimeters are in a inch?
1 inch = 25.4 millimeters.
What is the formula for inches to millimeters?
mm = in × 25.4.
How much is 10 in in mm?
10 in = 254 mm.