Length Converter
Convert between millimetres, centimetres, metres, kilometres, inches, feet, yards and miles.
Processing: This tool runs entirely in your browser. Your input and any file you open stay on your device — nothing is uploaded to a server.
How to use the length converter
- Type the amount you want to convert.
- Choose the unit you have and the unit you want.
- Read the result, or use the table showing all 10 units at once.
About this tool
Metric and imperial length units have an exact relationship: since 1959 an inch has been defined as precisely 25.4 millimetres. That means these conversions are not approximations — the only rounding is in how the result is displayed.
The table shows your amount in every unit at once, which is usually faster than converting twice when you are working between a metric drawing and an imperial tape measure.
Common uses
- Reading a measurement given in the other system.
- Converting a room size from feet to metres.
- Checking a part specification against a metric drawing.
Frequently asked questions
- How many centimetres are in an inch?
- Exactly 2.54. The inch is defined in terms of the metre, so it is a definition rather than a measurement.
- Why does a nautical mile differ from a mile?
- A nautical mile is 1,852 metres — one minute of latitude — which makes it useful for navigation. A statute mile is 1,609.344 metres.
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