The square foot (plural square feet; abbreviated ft² or sq ft) is an imperial unit and U.S. customary unit (non-SI non-metric) of area, used mainly in the United States, Canada, United Kingdom, Hong Kong, Bangladesh, India, Pakistan and Afghanistan. It is defined as the area of a square with sides of 1 foot (0.333... yards, 12 inches, or 0.3048 metres) in length. For comparison, the average new one-family house in the United States in 2007 had a total floor area of approximately 2500 square feet (232 square meters).
A symbol for square foot, square feet, and "per square foot" commonly used in architecture, real estate and interior space plans is a simple square with a vertical line bisecting it. It is also occasionally written as a square with a slash through it.
1 square foot is equivalent to:
- A tile 12 inches by 12 inches has a square foot area of 1 square foot. 12 inches is equal to 1 foot.
- 144 square inches (Sq In)
- 1/9 square yards (Sq Yd)
- 0.01 "squares". (A square is a unit used in roofing to measure the area of a roof and is also a unit used in Australia before metrication (and since) to measure the floor area of a house. 1 "square" = 100 sq ft)
- ≈0.00002295684 acres
- 92903.04 square millimetres (symbol: mm²)
- 929.0304 square centimetres (symbol: cm²)
- 0.09290304 square metres (symbol: m²)
- 0.00000009290304 square kilometres (symbol: km²)