The foot (pl. feet), abbreviation and IEEE standard symbol: ft, is a unit of length in the British imperial and United States customary systems of measurement. Since the International Yard and Pound Agreement of 1959, one foot is defined as 0.3048 meters exactly. In customary and imperial units, one foot comprises 12 inches and one yard comprises three feet.
The inch (symbol: in) is a unit of length in the (British) imperial and United States customary systems of measurement. Standards for the exact length of an inch have varied in the past, but since the adoption of the international yard during the 1950s and 1960s, it has been based on the metric system and defined as exactly 25.4 mm.