In to mm conversion formula
1 inch = 25.4 millimeter
The inch (in) is an imperial unit equal to exactly 2.54 centimeters since 1959, by international agreement. Widely used for screens, tools and body measurements.
The millimeter (mm) is one thousandth of a meter — the standard for engineering tolerances, rainfall and small parts.
In to mm conversion table
| in | mm |
|---|---|
| 1 in | 25.4 mm |
| 2 in | 50.8 mm |
| 3 in | 76.2 mm |
| 5 in | 127 mm |
| 10 in | 254 mm |
| 20 in | 508 mm |
| 25 in | 635 mm |
| 50 in | 1270 mm |
| 100 in | 2540 mm |
| 250 in | 6350 mm |
| 500 in | 12700 mm |
| 1000 in | 25400 mm |
How to convert in to mm
- Write down the value in in you want to convert.
- Multiply it by 25.4 — or use the converter above, which does it instantly.
- Read your result in mm. Done.
Frequently asked questions
How many mm is 1 in?
Using the official conversion factor, 1 inch = 25.4 millimeter. The converter above handles any value instantly.
What is the formula to convert inch to millimeter?
1 inch = 25.4 millimeter. Multiply any value in in by this factor to get mm.
Is this in to mm converter free?
Yes — 100% free, unlimited, with no sign-up. CalculUnits is funded by non-intrusive ads, never by paywalls.