The square foot is an imperial unit

Imperial unit

The system of imperial units or the imperial system is the system of units first defined in the British Weights and Measures Act of 1824, which was later refined and reduced. The system came into official use across the British Empire...

 and U.S. customary unit (non-SI

Si

Si, si, or SI may refer to :- Measurement, mathematics and science :* International System of Units , the modern international standard version of the metric system...

 non-metric

Metric system

The metric system is an international decimalised system of measurement. France was first to adopt a metric system, in 1799, and a metric system is now the official system of measurement, used in almost every country in the world...

) of area

Area

Area is a quantity that expresses the extent of a two-dimensional surface or shape in the plane. Area can be understood as the amount of material with a given thickness that would be necessary to fashion a model of the shape, or the amount of paint necessary to cover the surface with a single coat...

, 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

Square (geometry)

In geometry, a square is a regular quadrilateral. This means that it has four equal sides and four equal angles...

 with sides of 1 foot (0.333... yard

Yard

A yard is a unit of length in several different systems including English units, Imperial units and United States customary units. It is equal to 3 feet or 36 inches...

s, 12 inch

Inch

An inch is the name of a unit of length in a number of different systems, including Imperial units, and United States customary units. There are 36 inches in a yard and 12 inches in a foot...

es, or 0.3048 metre

Metre

The metre , symbol m, is the base unit of length in the International System of Units . Originally intended to be one ten-millionth of the distance from the Earth's equator to the North Pole , its definition has been periodically refined to reflect growing knowledge of metrology...

s) in length

Length

In geometric measurements, length most commonly refers to the longest dimension of an object.In certain contexts, the term "length" is reserved for a certain dimension of an object along which the length is measured. For example it is possible to cut a length of a wire which is shorter than wire...

. For comparison, the average new one-family house in the United States in 2007 had a total floor area of approximately 2500 square feet.

A symbol for square foot, square feet, and "per square foot" commonly used in architecture

Architecture

Architecture is both the process and product of planning, designing and construction. Architectural works, in the material form of buildings, are often perceived as cultural and political symbols and as works of art...

, real estate

Real estate

In general use, esp. North American, 'real estate' is taken to mean "Property consisting of land and the buildings on it, along with its natural resources such as crops, minerals, or water; immovable property of this nature; an interest vested in this; an item of real property; buildings or...

 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.

Conversions

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 inch
  Square inch
  A square inch is a unit of area, equal to the area of a square with sides of one inch. The following symbols are used to denote square inches:*square in*sq inches, sq inch, sq in*inches/-2, inch/-2, in/-2...
  
  es (Sq In)
• 1/9 square yard
  Square yard
  The square yard is an imperial/US customary unit of area, formerly used in most of the English-speaking world but now generally replaced by the square metre outside of the U.S., Canada and the U.K. It is defined as the area of a square with sides of one yard in length...
  
  s (Sq Yd)
• 0.01 "squares
  Square (building area)
  The square is an Imperial unit of area that is used in the United States construction industry, and was historically used in Australia. One square is equal to 100 square feet. Examples where the unit is used are roofing shingles, metal roofing, vinyl siding, and fibercement siding products...
  
  ". (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 acre
  Acre
  The acre is a unit of area in a number of different systems, including the imperial and U.S. customary systems. The most commonly used acres today are the international acre and, in the United States, the survey acre. The most common use of the acre is to measure tracts of land.The acre is related...
  
  s
• 92903.04 square millimetres (symbol: mm²)
• 929.0304 square centimetres (symbol: cm²)
• 0.09290304 square metre
  Square metre
  The square metre or square meter is the SI derived unit of area, with symbol m2 . It is defined as the area of a square whose sides measure exactly one metre...
  
  s (symbol: m²)
• 0.00000009290304 square kilometre
  Square kilometre
  Square kilometer, symbol km2, is a decimal multiple of the SI unit of surface area, the square metre, one of the SI derived units.1 km2 is equal to:* 1,000,000 m2* 100 ha * 0.386302 square miles* 247.105381 acresConversely:...
  
  s (symbol: km²)

See also

• 1 E-1 m²
  1 E-1 m²
  Image:Scale one to hundred no labels.svg|110px|right|Click on the small dark green top-left square for quantities smaller than 0.1 square metres, the mid green square for 0.1 to 1 square metres, the light green square for 10 to 100 square metres, and the pale green surround for over 100 square...
  
   for a comparison with other areas
• Cubic foot
  Cubic foot
  The cubic foot is an Imperial and US customary unit of volume, used in the United States and the United Kingdom. It is defined as the volume of a cube with sides of one foot in length.-Conversions:- Symbols :...
  
  
• Orders of magnitude (area)
  Orders of magnitude (area)
  This page is a progressive and labeled list of the SI area orders of magnitude, with certain examples appended to some list objects.-References:...
  
  
• Conversion of units
  Conversion of units
  Conversion of units is the conversion between different units of measurement for the same quantity, typically through multiplicative conversion factors.- Process :...
  
  
• Area (geometry)
• Square (algebra), square root
  Square root
  In mathematics, a square root of a number x is a number r such that r2 = x, or, in other words, a number r whose square is x...
  
  
• Miscellaneous Technical (Unicode)
  Miscellaneous Technical (Unicode)
  Miscellaneous Technical is the name of a a Unicode block ranging from U+2300 to U+23FF, which contains various common symbols which are related to and used in the various technical, programming language and academic professions....
  
  for a list of miscellaneous technical symbols and fonts which support the square foot symbol