Inches to Millimeters Converter
Convert inches to millimeters with a free calculator
How to Convert Inches to Millimeters
Formula: 1 in = 25.4 mm
Multiply your inches value by 25.4 to get the equivalent in millimeters. The conversion factor 25.4 is based on the internationally accepted definitions of both units.
Inches to Millimeters Reference Table
| Inches (in) | Millimeters (mm) |
|---|---|
| 1 in | 25.4 mm |
| 5 in | 127 mm |
| 10 in | 254 mm |
| 25 in | 635 mm |
| 50 in | 1,270 mm |
| 100 in | 2,540 mm |
| 500 in | 12,700 mm |
| 1000 in | 25,400 mm |
Related Conversions
Frequently Asked Questions
How many mm are in 1 inch? +
There are exactly 25.4 millimeters in 1 inch.
What is 1/4 inch in mm? +
1/4 inch equals 6.35 mm. Common fractional conversions: 1/8" = 3.175 mm, 1/2" = 12.7 mm, 3/4" = 19.05 mm.
Why is 25.4 mm per inch exact? +
The inch was redefined in 1959 as exactly 25.4 millimeters by international agreement among English-speaking nations.