How to convert inches to millimeters
Multiply the number of inches by 25.4. That is all there is to it, because the factor between inches and millimeters never changes.
Formula
mm = in × 25.4
Example: 10 inches × 25.4 = 254 millimeters.
Inches to MM chart
| Inches (in) | Millimeters (mm) |
|---|---|
| 0.25 in | 6.35 mm |
| 0.5 in | 12.7 mm |
| 1 in | 25.4 mm |
| 2 in | 50.8 mm |
| 3 in | 76.2 mm |
| 4 in | 101.6 mm |
| 5 in | 127 mm |
| 6 in | 152.4 mm |
| 8 in | 203.2 mm |
| 10 in | 254 mm |
| 12 in | 304.8 mm |
| 15 in | 381 mm |
| 18 in | 457.2 mm |
| 20 in | 508 mm |
| 24 in | 609.6 mm |
| 27 in | 685.8 mm |
| 30 in | 762 mm |
| 32 in | 812.8 mm |
| 36 in | 914.4 mm |
| 40 in | 1,016 mm |
| 43 in | 1,092.2 mm |
| 50 in | 1,270 mm |
| 55 in | 1,397 mm |
| 65 in | 1,651 mm |
| 75 in | 1,905 mm |
Values are rounded to six decimals below 1, four decimals up to 1,000 and two decimals above. The converter above shows more digits.
About the units
One inch is 0.0254 meters.
One millimeter is 0.001 meters.
Need the other direction? Use the MM to Inches converter. For every length unit at once, open the Length Converter.
Frequently asked questions
How many millimeters are in an inch?
There are 25.4 millimeters in one inch.
How do I convert inches to millimeters?
Multiply the number of inches by 25.4. For example: 10 inches × 25.4 = 254 millimeters.
What is 27 inches in millimeters?
27 inches equals 685.8 millimeters.