Convert Square Foot (ft²) to Acre (US Survey) (ac (US)) instantly.
About these units
Square Foot (ft²)
A square foot is the area of a square one foot on each side. It is widely used in the United States, the UK (historically), Canada (in real estate), and other regions where imperial units remain culturally influential. Square feet dominate property listings, architectural blueprints, and interior design specifications in the US. The measurement provides an intuitive scale for rooms and buildings, fitting well with common human-scaled dimensions. Although metrication has reduced its use worldwide, the square foot remains deeply embedded in construction codes, real estate markets, and consumer expectations in countries that continue to rely on imperial or hybrid systems. Its survival highlights the cultural persistence of traditional measurement systems despite global standardization.
Acre (US Survey) (ac (US))
The US survey acre is based on the US survey foot, making it slightly different from the international acre. With a value of 43,560 survey-square feet, it appears extensively in historical property records and federal land surveys. Because millions of acres in the United States were mapped using PLSS, the survey acre remains necessary for interpreting legal land rights, even though modern mapping often uses metric units or the international foot. This specialized acre illustrates how subtle unit differences can survive for centuries due to legal and administrative inertia.