Inches to Millimeters (in to mm)
1 inch = 25.4 millimeters
How to convert inches to millimeters
mm = in × 25.4
Example: 6 × 25.4 = 152.4, so 6 inches = 152.4 millimeters.
Fractional inch sizes such as 1/8, 3/8 or 5/8 inch appear on US hardware, pipe fittings and woodworking plans. Converting them to millimeters helps you find the matching metric part.
Enter fractions as decimals: 1/16 = 0.0625, 1/8 = 0.125, 1/4 = 0.25, 3/8 = 0.375, 1/2 = 0.5, 5/8 = 0.625 and 3/4 = 0.75.
Inches to Millimeters conversion table
| Inches (in) | Millimeters (mm) |
|---|---|
| 0.0625 in | 1.5875 mm |
| 0.125 in | 3.175 mm |
| 0.1875 in | 4.7625 mm |
| 0.25 in | 6.35 mm |
| 0.3125 in | 7.9375 mm |
| 0.375 in | 9.525 mm |
| 0.5 in | 12.7 mm |
| 0.625 in | 15.875 mm |
| 0.75 in | 19.05 mm |
| 0.875 in | 22.225 mm |
| 1 in | 25.4 mm |
| 1.25 in | 31.75 mm |
| 1.5 in | 38.1 mm |
| 2 in | 50.8 mm |
| 3 in | 76.2 mm |
| 4 in | 101.6 mm |
| 6 in | 152.4 mm |
| 12 in | 304.8 mm |
What is a inch?
The inch has been defined as exactly 2.54 centimeters since the 1959 international yard and pound agreement. Screens, tyres, pipes and US body measurements are still quoted in inches; 12 inches make a foot.
What is a millimeter?
A millimeter is one thousandth of a meter. It is the standard unit on engineering drawings, for screw and drill sizes, rainfall totals and smartphone dimensions.
Frequently asked questions
How many millimeters are in one inch?
One inch equals 25.4 millimeters.
How do I convert inches to millimeters?
Use the formula mm = in × 25.4. 6 × 25.4 = 152.4, so 6 inches = 152.4 millimeters.
What is 12 in in mm?
12 in = 304.8 mm.
How do I convert millimeters back to inches?
Use the inverse formula in = mm ÷ 25.4, or open the Millimeters to Inches converter.
More length conversions
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