Acre

:This article is about the unit of measure known as the acre. For other definitions, see Acre (disambiguation).

US definition

The US has a definition of the acre in NIST Handbook 44 as 43 560 square feet. However, the US has two definitions of foot (international foot and survey foot) and thus two definitions of acre:

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• The international acre is 4 046.856 422 4 m². This is based on international foot of 0.3048 m.
• The US survey acre is 4 046.872 61 m². This is based on the US 'survey foot of 1200/3937 m.