Acre

For the state in Brazil, see Acre (state).

An acre is an English unit of area, which is also used in the United States and some Commonwealth countries. It is most often used to describe areas of land.

• By the official definition it is 4,046.8564224 m² (4,840 square yards). It is the area of one furlong by one chain.
• The international acre is 4,046.8564224 m², or 0.404686 hectares. This is based on international foot of 0.3048 m.

An acre is approximately equal:

• the area of an American football field.

Originally, it was seen as the area of land a farmer could plough with an ox in a day. Since this definition depended on the farmer and the ox, it looked variable. Therefore, Edward I, Edward III, Henry VIII and George IV passed laws fixing its size. The Commonwealth countries, including the United States then also introduced these laws.

Acre Media

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  Image comparing the acre (the small pink area at lower left) to other units. The entire yellow square is one square mile; the dark blue area at right represents 100 acres.

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  The area of one acre (red) superposed on an American football field (green) and Association football/soccer pitch (blue).

Other websites

• The Units of Measurement Regulations 1995
• NIST Handbook 44 Archived 2004-12-04 at the Wayback Machine