Inches to Millimeters Converter
Use this free inches to millimeters converter to get an exact answer as you type. 1 inch equals 25.4 millimeters, so the conversion is simple – the calculator also accepts fractions such as 5 3/8 and shows the result as a fraction of an inch when it helps.
How to convert inches to millimeters
- Type the length in inches into the Value box. Fractions like 3/8 and mixed numbers like 5 3/8 are accepted.
- Check that “From” shows inches and “To” shows millimeters. Use the swap button to reverse the direction.
- Read the exact answer instantly. Choose how many decimals you need, and copy the result with one tap.
The inches to millimeters formula
To convert inches to millimeters, multiply the number of in by 25.4. In short: mm = in × 25.4. Example: 10 in = 254 mm.
Inches to millimeters conversion table
Look up the most common values below. For any other number, use the calculator above.
| Inches (in) | Millimeters (mm) |
|---|---|
| 0.25 | 6.35 |
| 0.5 | 12.7 |
| 0.75 | 19.05 |
| 1 | 25.4 |
| 1.5 | 38.1 |
| 2 | 50.8 |
| 2.5 | 63.5 |
| 3 | 76.2 |
| 3.5 | 88.9 |
| 4 | 101.6 |
| 4.5 | 114.3 |
| 5 | 127 |
| 5.5 | 139.7 |
| 6 | 152.4 |
| 7 | 177.8 |
| 8 | 203.2 |
| 9 | 228.6 |
| 10 | 254 |
| 11 | 279.4 |
| 12 | 304.8 |
| 13 | 330.2 |
| 14 | 355.6 |
| 15 | 381 |
| 16 | 406.4 |
| 17 | 431.8 |
| 18 | 457.2 |
| 19 | 482.6 |
| 20 | 508 |
| 21 | 533.4 |
| 22 | 558.8 |
| 23 | 584.2 |
| 24 | 609.6 |
| 25 | 635 |
| 26 | 660.4 |
| 27 | 685.8 |
| 28 | 711.2 |
| 29 | 736.6 |
| 30 | 762 |
| 32 | 812.8 |
| 34 | 863.6 |
| 36 | 914.4 |
| 40 | 1,016 |
| 42 | 1,066.8 |
| 48 | 1,219.2 |
| 50 | 1,270 |
| 55 | 1,397 |
| 60 | 1,524 |
| 65 | 1,651 |
| 70 | 1,778 |
| 72 | 1,828.8 |
| 75 | 1,905 |
| 80 | 2,032 |
| 90 | 2,286 |
| 100 | 2,540 |
About these units
The inch (in or ″) is defined as exactly 2.54 centimeters. It is used in the United States, the United Kingdom and Canada, and for screen sizes, tires and pipes worldwide.
The millimeter (mm) is one thousandth of a meter. It is the standard unit for precise measurements in engineering, woodworking, 3D printing and hardware.
Frequently asked questions
How many millimeters are in 1 in?
1 in = 25.4 mm. This factor is exact by definition.
How do I convert inches to millimeters?
Multiply the value in in by 25.4. For example, 10 in = 254 mm.
How many millimeters is 36 in?
36 in = 914.4 mm.
Is this inches to millimeters converter accurate?
Yes. It uses the exact international definitions (1 inch = 2.54 cm, 1 foot = 30.48 cm). Numbers are rounded only for display, and you can show up to 8 decimals.