What Is a Foot (ft)?
Definition
Foot (ft): A unit of length used in the United States and the United Kingdom, symbol ft. One foot is 12 inches and, since 1959, exactly 0.3048 meters by definition.
The foot (plural feet, symbol ft) is a unit of length used in the United States and the United Kingdom for heights and aircraft altitude. One foot is 12 inches and, since the 1959 international yard and pound agreement, exactly 0.3048 meters. Three feet make a yard, and 5,280 feet make a mile.
Where it appears in the formulas
1 ft = 12 in = 0.3048 m. The length converter uses this exact factor (NIST SP 811, Appendix B; NIST Handbook 44, Appendix C). For example, 6 feet is 6 × 0.3048 = 1.8288 m, and 1 meter is about 3.2808 feet.
US survey foot
The old US survey foot differs very slightly from the international foot. The length converter does not use it.