Length Converter
Convert between metres, feet, inches, miles and more.
Good to know. An inch is exactly 2.54 cm, by international agreement since 1959.
How it works
In plain words
Convert the value into metres using the exact size of the unit, then from metres into the target unit.
The formula
result = value × (metres per "from" unit) ÷ (metres per "to" unit) 1 in = 2.54 cm · 1 ft = 0.3048 m · 1 mi = 1.609344 km
Worked example
10 inches × 2.54 = 25.4 cm.
Sources
- NIST Special Publication 811, Guide for the Use of the International System of Units, Appendix B Exact conversion factors for US customary units.
- International yard and pound agreement, 1959 1 yard = 0.9144 m and 1 pound = 0.45359237 kg exactly, so 1 inch = 2.54 cm and 1 mile = 1.609344 km.
Sources checked September 29, 2026. 9 automated tests check its answers on every change.
About the length converter
Most of the world measures length in metres, but inches, feet, yards and miles are still everyday units in the United States and, for some things, the UK: heights, screen sizes, road distances and DIY measurements.
The good news is that the relationship is exact. Since an international agreement in 1959, one inch is exactly 2.54 centimetres. Everything else follows from that: a foot is 12 inches (30.48 cm), a yard is 3 feet (91.44 cm) and a mile is 1,760 yards (1.609344 km). So there is no rounding in these conversions apart from the final display.
A nautical mile, used at sea and in the air, is different: it is exactly 1,852 metres, based originally on one minute of latitude.
Some quick mental shortcuts: a metre is a little more than a yard (about 1.09 yards). A kilometre is about 0.62 miles, so 5 km is just over 3 miles. To turn miles into kilometres roughly, multiply by 8 and divide by 5. Your height in centimetres divided by 2.54 gives inches; divide by 12 for feet.
The table below the result shows your value in every unit at once, which is handy when you don’t know which one you need.
Questions people ask
How many centimetres are in an inch?
Exactly 2.54.
How do I convert feet to metres?
Multiply by 0.3048. 6 feet is 1.8288 metres.
How many miles is a kilometre?
About 0.621371. So 10 km is about 6.21 miles.
How do I convert my height from cm to feet and inches?
Divide by 2.54 to get inches, then divide by 12. The whole number is feet, and the remainder is inches. 175 cm is 68.9 in, or 5 ft 8.9 in.