Inches to Mm ConverterRight in Your Browser
Convert inches (in) to millimeters (mm). The inch (in) is the small imperial length unit used in the US and UK for screens, paper and DIY measurements. The millimeter (mm) is one thousandth of a meter, the precision unit for engineering, hardware and rainfall. Everything is calculated locally in your browser — no server, and it works offline.
25.4 mm
in millimeters (millimeter)
To convert inches to millimeters, multiply the inch value by 25.4.
Switch to Mm to InchesInches to Mm Chart
| Inches (in) | Millimeters (mm) |
|---|---|
| 1 | 25.4 |
| 2 | 50.8 |
| 3 | 76.2 |
| 4 | 101.6 |
| 5 | 127 |
| 10 | 254 |
| 20 | 508 |
| 50 | 1270 |
| 100 | 2540 |
Frequently Asked Questions
How many millimeters are in a inch?
One inch equals 25.4 millimeters (1 in = 25.4 mm). So to go from inches to millimeters, multiply the inch value by 25.4.
What is the formula to convert inches to millimeters?
To convert inches to millimeters, multiply the inch value by 25.4. For example, 10 in is 254 mm.
What is 6.1 inches in millimeters?
6.1 inches — a smartphone screen diagonal — is 154.94 millimeters. The converter above works for any value, entirely in your browser.
Is the inch to millimeter conversion exact?
The factor used here is the defined value: 1 in = 25.4 mm. Results are rounded to six significant digits for readability, so for high-precision work use the full factor.