Inches to MM converter
1 in = 25.4 mm, so multiply by 25.4. Example: 1 in = 25.4 mm.
25.4 mm
1 in = 25.4 mm
1 inch in every length unit
millimetre25.4 mm
centimetre2.54 cm
metre0.0254 m
kilometre0.0000254 km
foot0.08333333 ft
yard0.02777778 yd
mile0.0000157828 mi
nautical mile0.0000137149 nmi
micrometre25,400 µm
Inches to MM chart
| inch (in) | millimetre (mm) |
|---|---|
| 1/64 (0.015625) | 0.396875 |
| 1/32 (0.03125) | 0.79375 |
| 1/16 (0.0625) | 1.5875 |
| 1/8 (0.125) | 3.175 |
| 3/16 (0.1875) | 4.7625 |
| 1/4 (0.25) | 6.35 |
| 5/16 (0.3125) | 7.9375 |
| 3/8 (0.375) | 9.525 |
| 7/16 (0.4375) | 11.1125 |
| 1/2 (0.5) | 12.7 |
| 9/16 (0.5625) | 14.2875 |
| 5/8 (0.625) | 15.875 |
| 11/16 (0.6875) | 17.4625 |
| 3/4 (0.75) | 19.05 |
| 13/16 (0.8125) | 20.6375 |
| 7/8 (0.875) | 22.225 |
| 15/16 (0.9375) | 23.8125 |
| 1 | 25.4 |
| 1.25 | 31.75 |
| 1.5 | 38.1 |
| 1.75 | 44.45 |
| 2 | 50.8 |
| 2.5 | 63.5 |
| 3 | 76.2 |
| 4 | 101.6 |
| 5 | 127 |
| 6 | 152.4 |
| 8 | 203.2 |
| 10 | 254 |
| 12 | 304.8 |
How to convert inches to mm
Formula: mm = inches × 25.4
Worked example: 1 in → 25.4 mm.
One inch is exactly 25.4 mm, so a 1/4-inch bolt is 6.35 mm and a 1/8-inch drill bit is 3.175 mm.
You can type a fraction straight into the box, such as 3/8 or 1/16, and it is converted exactly.
Need another unit? The length converter handles every length unit.
Questions people ask
How many millimetres are in one inch?
One inch is 25.4 millimetres.
What is the formula for inches to mm?
mm = inches × 25.4. One inch is exactly 25.4 mm, so a 1/4-inch bolt is 6.35 mm and a 1/8-inch drill bit is 3.175 mm.
What is 1/4 (0.25) in in mm?
1/4 (0.25) in = 6.35 mm.
What is 3/8 (0.375) in in mm?
3/8 (0.375) in = 9.525 mm.
What is 1.5 in in mm?
1.5 in = 38.1 mm.