Length Converter
Convert between metric and imperial length units.
How to use the Length Converter
- Type the number into Value. The page opens on Centimeter to Inch.
- Choose the unit you are starting from in the From list, then the one you want in the To list.
- Read the answer below. It updates as you type, so there is nothing to submit.
The exact factors behind each conversion
Every value passes through metres: multiplied by the From factor, divided by the To factor, then rounded to six decimals. Inch and foot use their exact definitions, so one inch is 2.54 cm to the last digit.
| Unit | Metres |
|---|---|
| Millimeter | 0.001 |
| Centimeter | 0.01 |
| Meter | 1 |
| Kilometer | 1000 |
| Inch | 0.0254 |
| Foot | 0.3048 |
| Mile | 1609.34 |
Where six decimal places runs out
Since results round to six decimals, a very small answer collapses. One millimetre in miles is about 0.00000062 and prints as 0.000001. Convert into a smaller unit and scale it yourself.
Frequently asked questions
Which conversions are most used?
Centimetres to inches and kilometres to miles come up most often, usually when reading overseas product specs or road distances.
How precise is it?
Results are rounded to six decimal places. One caveat: the mile is stored as 1609.34 metres rather than the exact 1609.344, so mile results are good to about six significant figures.
How many centimetres are in an inch?
Exactly 2.54. The inch has been defined as 0.0254 metres since 1959, so it is a definition, not a measurement. One centimetre is 0.393701 inches.
Is a mile the same in the UK and the US?
Yes for the statute mile, 1609.344 metres in both. The nautical mile is a different unit at 1852 metres and is not on this list.
Why is there no convert button?
The result recalculates on every keystroke and on any change to the From or To list, so there is nothing to submit.