foot squared (square foot)

The foot squared, also called the square foot, is the standard unit of area in the English foot-pound-second (fps) system. The symbol for foot or feet squared is ft². Less formally, square foot or feet is sometimes abbreviated sq ft.

When calculating area, it is important to realize that area is proportional to the square of the linear dimension. Thus, if all linear dimensions are doubled, the area becomes four times (2²) as great; if all linear dimensions are cut in half, the area becomes 1/4 (1/2²) as great. An area of 1 ft² is equal to 144 inches squared (144 in²), but only 1/9 of a yard squared (1/9 yd²).

When converting between feet squared and metric units of area such as meters squared (m²) or centimeters squared (cm²), the linear-unit conversion factor must be squared. To convert feet squared approximately to meters squared, multiply by 0.09290. Conversely, multiply by 10.76. To convert feet squared approximately to centimeters squared, multiply by 929.0. Conversely, multiply by 0.001076.

Also see area, meter, meter squared, centimeter squared, circular mil, International System of Units (SI), and Table of Physical Units.