Length and distance converter
Millimetres, centimetres, metres, kilometres, inches, feet, yards, miles and nautical miles, converted both ways.
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Use this for anything measured in a straight line: furniture and screen sizes in inches, room dimensions in feet, running distances in kilometres or miles, and sea or air distances in nautical miles. Type in either box and both stay in sync.
All imperial lengths are exact multiples of the metre. The 1959 agreement fixed the inch at exactly 25.4 mm, so a foot is 0.3048 m, a yard 0.9144 m and a mile (1760 yards) 1609.344 m. The international nautical mile is defined as exactly 1852 m; it is used in aviation and shipping because one nautical mile is approximately one minute of latitude.
Going the other way, a metre is about 3.28084 ft or 39.3701 in and a kilometre about 0.621371 mi. The table under the converter lists common values for whatever pair you have selected.
How to use it
- Pick the unit you are starting from and the unit you want.
- Type the length in either box; the result updates as you type.
- Swap the units with the ⇄ button, and set decimals if you need a rounded figure.
Frequently asked questions
How many centimetres are in an inch?
Exactly 2.54 cm (25.4 mm). This has been the legal definition of the inch in the US, UK, Canada, Australia and other countries since 1959.
What is a nautical mile and when is it used?
A nautical mile is exactly 1852 m (about 1.1508 statute miles). Pilots and sailors use it, together with knots (nautical miles per hour), because it corresponds closely to one minute of arc of latitude on a chart.
How do I convert a height such as 5 ft 9 in?
Use the feet-and-inches to cm converter, which takes feet and inches in separate boxes. 5 ft 9 in is 69 in, or exactly 175.26 cm.
Is a survey foot different?
The US survey foot (1200/3937 m) was used in some land surveys; it differs from the international foot by 2 parts per million. NIST retired it at the end of 2022, and this converter uses the international foot, 0.3048 m.
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