Length Converter
Convert between metric and imperial lengths, from millimeters on a technical drawing to miles on a road sign. Every imperial length here is defined exactly in metric terms, so the results are exact up to the decimals shown.
inches
1 cm = 0.3937 in
Popular length conversions
Units in this converter
| Unit | Symbol | Equals (in meters) |
|---|---|---|
| Millimeter | mm | 0.001 m |
| Centimeter | cm | 0.01 m |
| Meter | m | 1 m |
| Kilometer | km | 1,000 m |
| Inch | in | 0.0254 m |
| Foot | ft | 0.3048 m |
| Yard | yd | 0.9144 m |
| Mile | mi | 1,609.344 m |
How metric and imperial lengths relate
Since 1959 the inch has been exactly 2.54 cm. Every other imperial length is a whole multiple of the inch: a foot is 12 inches, a yard is 3 feet and a mile is 1,760 yards. That makes conversions like 1 ft = 30.48 cm and 1 mi = 1.609344 km exact.
About the units
- Millimeter (mm)
- The millimeter is one thousandth of a meter. It is the standard unit on engineering and architectural drawings, and it is used for small, precise dimensions such as screw diameters, rainfall totals and the thickness of a phone.
- Centimeter (cm)
- The centimeter is one hundredth of a meter, or 10 millimeters. In most of the world it is the everyday unit for body height, clothing measurements and anything you would measure with a school ruler.
- Meter (m)
- The meter is the SI base unit of length. Since 1983 it has been defined by the speed of light: it is the distance light travels in a vacuum in 1/299,792,458 of a second.
- Kilometer (km)
- The kilometer equals 1,000 meters. Road distances, running races and map scales use it almost everywhere, with the United States and the United Kingdom as the main exceptions for road signs.
- Inch (in)
- The inch has been defined as exactly 2.54 centimeters since the 1959 international yard and pound agreement. It is used worldwide for screen sizes and wheel diameters, and in the US for most short measurements.
- Foot (ft)
- The foot equals 12 inches, which is exactly 0.3048 meters. Americans use it for height and room dimensions, and aviation uses it worldwide for altitude. The slightly different US survey foot was officially retired at the end of 2022.
- Yard (yd)
- The yard equals 3 feet or 36 inches, exactly 0.9144 meters. It remains common for American football fields, golf distances and fabric sold by length.
- Mile (mi)
- The international mile is 5,280 feet, exactly 1,609.344 meters. Road signs in the US and the UK use it. It is different from the nautical mile (1,852 meters) used at sea and in aviation.
Frequently asked questions
Is an inch exactly 2.54 cm?
Yes. The international inch was defined as exactly 2.54 centimeters in 1959, so any conversion between inches and metric units is exact.
How do I convert my height to feet and inches?
Convert your height to inches, then divide by 12. The whole number is feet and the remainder is inches. For example, 175 cm is 68.9 inches, which is 5 feet 8.9 inches.