inches to mm converter
1 inch equals 25.4 millimeters. Conversions use mm = in × 25.4
in → 25.4 mm
mm = in × 25.4
Converter
Worked examples
- 1 in = 25.4 mm
- 2 in = 50.8 mm
- 5 in = 127 mm
- 10 in = 254 mm
- 100 in = 2,540 mm
inches to millimeters conversion table
| in | mm | Arithmetic |
|---|---|---|
| 0.25 in | 6.35 mm | × 25.4 |
| 0.5 in | 12.7 mm | × 25.4 |
| 0.75 in | 19.05 mm | × 25.4 |
| 1 in | 25.4 mm | × 25.4 |
| 2 in | 50.8 mm | × 25.4 |
| 3 in | 76.2 mm | × 25.4 |
| 4 in | 101.6 mm | × 25.4 |
| 5 in | 127 mm | × 25.4 |
| 6 in | 152.4 mm | × 25.4 |
| 8 in | 203.2 mm | × 25.4 |
| 10 in | 254 mm | × 25.4 |
| 12 in | 304.8 mm | × 25.4 |
| 15 in | 381 mm | × 25.4 |
| 20 in | 508 mm | × 25.4 |
| 25 in | 635 mm | × 25.4 |
| 30 in | 762 mm | × 25.4 |
| 40 in | 1,016 mm | × 25.4 |
| 50 in | 1,270 mm | × 25.4 |
| 60 in | 1,524 mm | × 25.4 |
| 70 in | 1,778 mm | × 25.4 |
| 80 in | 2,032 mm | × 25.4 |
| 90 in | 2,286 mm | × 25.4 |
| 100 in | 2,540 mm | × 25.4 |
How to convert in to mm
- Take your value in inches.
- Multiply by 25.4
- That is your answer in millimeters — no rounding needed until you choose a display precision.
Related conversions
mm to inmm to cmmm to mmm to kmmm to ftmm to ydmm to mimm to nmicm to mmall length units
Questions
How many millimeters in 1 inch?
Exactly 25.4 mm. The factor follows from the definitions of both units, not from a measurement, so it is exact.
How do I convert in to mm?
Multiply the inches figure by 25.4 — or use the converter above, which updates as you type.
Is in to mm the same as mm to in?
No — they are inverses. One in is 25.4 mm, while one mm is 0.03937008 in.
What is 0.25 in in mm?
0.25 in = 6.35 mm (see the value page for the full arithmetic).