Convert inches to millimeters
1 inch equals 25.4 millimeters. Type any number below — the other side updates instantly.
Inches to millimeters — quick reference
| inches | millimeters |
|---|---|
| 0.125 in | 3.175 mm |
| 0.25 in | 6.35 mm |
| 0.5 in | 12.7 mm |
| 0.75 in | 19.05 mm |
| 1 in | 25.4 mm |
| 1.5 in | 38.1 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 |
| 16 in | 406.4 mm |
| 24 in | 609.6 mm |
| 36 in | 914.4 mm |
| 48 in | 1219.2 mm |
How to convert
Multiply the number of inchs by 25.4 to get millimeters. To go the other way, multiply millimeters by 0.03937 to get inchs. The conversion factor is fixed and exact, so you can use this on any value.
About these units
Inches
- Definition
- An inch (symbol: in) is a unit of length in the imperial and US customary systems, defined as exactly 25.4 mm. There are 12 inches in a foot.
- History
- The word inch derives from the Latin uncia ("one-twelfth"). Standards historically included the length of three barley grains end-to-end.
- Current use
- The inch is dominant in the United States, Canada, and the UK. It is used worldwide for screen sizes (TVs, laptops, phones) and certain engineering standards.
Millimeters
- Definition
- A millimeter (symbol: mm) is one-thousandth of a meter, the SI base unit of length. It equals 0.1 cm or about 0.0394 inches.
- History
- The millimeter was defined alongside the meter in 1799 as part of the original metric system in revolutionary France. It became part of the modernized SI in 1960.
- Current use
- Millimeters are the dominant unit for technical drawings, hardware tolerances, screen sizes, and any small measurement in metric countries.
Frequently asked
- How many millimeters are in 1 inch?
- 1 inch = 25.4 millimeters.
- How do you convert inches to millimeters?
- Multiply the number of inchs by 25.4 to get millimeters. To go the other way, multiply millimeters by 0.03937 to get inchs. The conversion factor is fixed and exact, so you can use this on any value.
- What is 5 inches in millimeters?
- 5 inches = 127 millimeters.
Convert inches to other length units
Convert other length units to millimeters
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