The square foot (; abbreviated sq ft, sf, or ft<sup>2</sup>; also denoted by ô<sup><sup>2</sup></sup> and âÂÂ) 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. Dimensions are generally taken with a laser device, the latest in a long line of tools used to gauge the size of apartments 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.
1 square foot conversion to other units of area: