Square foot

square foot
The world's smallest park, which is 2.6 square feet (0.24 m2) in area
General information
Unit system	Imperial, United States customary units
Unit of	area
Symbol	ft2, sq ft
Conversions
1 ft2 in ...	... is equal to ...
Imperial/US	144 sq in ⁠1/9⁠ sq yd
SI units	929.0304 cm2 0.09290304 m2

The square foot (pl. square feet; abbreviated sq ft, sf, or ft²; also denoted by ´² and ⏍) is an imperial unit and U.S. customary unit (non-SI, non-metric) of area, used mainly in the United States, Canada, the United Kingdom, Bangladesh, India, Nepal, Pakistan, Ghana, Liberia, Malaysia, Myanmar, Singapore and Hong Kong. It is defined as the area of a square with sides of 1 foot.

Although the pluralization is regular in the noun form, when used as an adjective, the singular is preferred. So, an apartment measuring 700 square feet could be described as a 700 square-foot apartment. This corresponds to common linguistic usage of foot.

The square foot unit is commonly used in real estate.¹ Dimensions are generally taken with a laser device, the latest in a long line of tools used to gauge the size of apartments² or other spaces. Real estate agents often measure straight corner-to-corner, then deduct non-heated spaces, and add heated spaces whose footprints exceed the end-to-end measurement.³

Square foot conversion to other units of area:

• 1⁄27,878,400 ≈ 0.0000000358701 square miles (mi²)
• 1⁄43,560 ≈ 0.000022956341 acre (ac)
• 1⁄9 ≈ 0.111111111111 square yard (yd²)
• 144 square inches (in²)

• 0.000009290304 hectare (ha)
• 0.0009290304 are (a, uncommon)
• 0.09290304 square meters (m²)
• 9.290304 square decimeters (dm², uncommon)
• 929.0304 square centimeters (cm²)
• 92,903.04 square millimeters (mm²)