Acre

An acre is the name of a unit of area in a number of different systems, including Imperial units and United States customary units. The most commonly used acres today are the international acre and, in the United States, the survey acre.

One acre comprises 4,840 square yards or 43,560 square feet. Because of alternative definitions of a yard or a foot, the exact size of an acre also varies slightly. Traditionally, an acre was a swath of land one furlong long and one chain wide. A modern acre can have arbitrary dimensions as long as the area is correct. For example, a strip of land 1 inch wide and 99 miles long is also an acre.

The acre is often used to express areas of land. In the metric system, the hectare is commonly used for the same purpose. An acre is approximately 0.4 hectare.

One acre is 90.75 yards of a 53.33-yard-wide American football field. The full field, including the end zones, covers approximately 1.32 acres.