Foot(ft)
The foot (ft) is a non-SI unit of length equal to exactly 0.3048 meters in the international definition.
Reviewed
- Symbol
- ft
- Quantity
- Length
- Measurement system
- Imperial and US customary
- SI classification
- Non-SI unit
- Reference unit
- Meter
- Exact relationship
- 1 ft = 0.3048 m exactly
Visualizing foot
The international foot
The international foot is defined as exactly 0.3048 meters. This definition has been used since 1959 and is the standard conversion for general, construction, aviation, and everyday measurements.
International foot and U.S. survey foot
Historical surveying records may use the U.S. survey foot, which was defined as exactly 1,200/3,937 meters. It is slightly longer than the international foot and was retired from new U.S. federal use in 2023. Always identify the variant when working with geospatial or legacy data.
Where feet are used
Feet remain common in the United States and are also used in specific contexts in countries that otherwise use the metric system, such as aviation altitude and some construction or property measurements.
Feet, inches, and notation
A foot contains 12 inches. In informal measurements, feet and inches may be written with prime and double-prime marks, such as 6′ 2″ for six feet two inches. The abbreviation ft is unambiguous in technical writing.