About inches and millimetres
An inch (in) is an imperial and US unit of length. There are 12 inches in a foot, and one inch is exactly 2.54 centimetres.
A millimetre (mm) is one thousandth of a metre. It is used for small measurements in engineering, manufacturing and rainfall.
How the conversion works
Converts inches to millimetres, and back again. Type a value in either box and the other one updates as you type. The conversion uses 1 inch = 25.4 millimetres.
Inch to Millimetre conversion table
| inches | millimetres |
|---|---|
| 1 inch | 25.4 millimetres |
| 2 inches | 50.8 millimetres |
| 5 inches | 127 millimetres |
| 10 inches | 254 millimetres |
| 25 inches | 635 millimetres |
| 50 inches | 1,270 millimetres |
| 100 inches | 2,540 millimetres |
| 1,000 inches | 25,400 millimetres |
How to use it
- Enter a value in inches to see it in millimetres, or type in the other box to convert the opposite way.
- Check the quick conversion table below for common values.
- To convert by hand, multiply the number of inches by 25.4.
Did you know?
- The inch was fixed at exactly 2.54 centimetres by an international agreement in 1959.
- A standard bank card is 0.76 millimetres thick.