Foot (ft)
Definition
The foot (symbol ft, plural feet) is an imperial and US customary unit of length equal to exactly 0.3048 meters. One foot contains 12 inches and three feet make a yard.
History
The foot draws on anatomical roots common to many ancient cultures, with the Roman pes of about 296 mm influencing later European feet. Medieval England used several feet of slightly different lengths before the statute foot was codified during the reign of Edward I.
The 1959 international yard and pound agreement, signed by the United States, the United Kingdom, Canada, Australia, New Zealand, and South Africa, fixed the international foot at exactly 0.3048 meters. The US survey foot, defined as 1200/3937 m and roughly 2 ppm larger, persisted for geodetic work but was officially retired on 1 January 2023, leaving only the international foot in legal use.
Standard reference
Defined under the 1959 international yard and pound agreement as exactly 0.3048 m. Listed in NIST Special Publication 811 and NIST Handbook 44.
Common conversions
| 1 ft | = 0.3048 m |
|---|---|
| = 30.48 cm | |
| = 12 in | |
| = 0.333333 yd |