Length Converter
Convert between meters, feet, inches, miles, and more
Quick Reference
How to use this tool
- Enter a value in the input field
- Select the unit you're converting from
- Select the unit you're converting to
- The result updates automatically
About this tool
Convert a distance between metric and imperial units, in either direction, with the result updating as you type. The units cover metres, kilometres, centimetres and millimetres on the metric side, and miles, yards, feet and inches on the imperial side, plus nautical miles for navigation. Between them they handle almost every everyday conversion: a height given in centimetres that has to go on a form in feet and inches, a running distance in kilometres you want in miles, a component measured in millimetres against a drawing in inches, or a room dimension quoted in one system and needed in the other. The factors are exact rather than approximate. Since 1959 an inch has been defined as exactly 2.54 centimetres, which makes a foot exactly 30.48 centimetres, a yard exactly 0.9144 metres and a mile exactly 1,609.344 metres. Those are definitions, not measurements, so a conversion is only ever limited by how many decimal places are displayed. Nautical miles are the exception worth knowing about. At 1,852 metres, a nautical mile is one minute of latitude, which is why sea and air navigation use it: distance on a chart maps directly onto the coordinate grid, and speed in knots is nautical miles per hour. Everything is calculated in your browser, with no network call and nothing stored.
Frequently asked questions
How many centimetres are in an inch?
Exactly 2.54, by international agreement since 1959. That makes a foot exactly 30.48 centimetres and a yard exactly 0.9144 metres, so these conversions are definitional rather than measured approximations.
How do I convert feet and inches to metres?
Convert the whole thing to inches first, by multiplying the feet by twelve and adding the inches, then convert that total. Five foot ten is 70 inches, which is 1.778 metres. Converting each part separately and adding the results is where people usually go wrong.
How many kilometres is a mile?
1.609344, so a mile is a little over one and a half kilometres. Working the other way, a kilometre is about 0.621 miles, which is why a 5K race is a shade over three miles.
What is a nautical mile and why is it different?
It is 1,852 metres, defined as one minute of latitude, which makes it the natural unit for navigation because distance on a chart maps directly onto the coordinate grid. That is why aviation and shipping use it and knots, one nautical mile per hour, rather than land miles.
How accurate are the results?
They use the exact internationally defined factors and are rounded only for display. Converting a value and converting it straight back may differ in the final decimal place, which is rounding rather than error.
Is my data sent to a server?
No. The arithmetic happens in your browser, so the tool keeps working offline once the page has loaded and nothing you type leaves your device.