Square Feet to Acres (ft² to ac)

1 square foot equals 0.00002295684114 acres (rounded).

1 square foot = 0.00002295684114 acres

How to convert square feet to acres

To convert square feet to acres, multiply the number of square feet by 0.00002295684114. The factor is rounded to 10 significant digits. To go the other way, multiply acres by 43,560.

acres = square feet × 0.00002295684114

Example: 10 square feet = 0.0002295684114 acres.

About these units

Square Foot (ft²)

US & ImperialCurrent unit

Exactly 0.09290304 m². The standard unit for floor areas and real estate in the US, UK and India.

Feet came first, and they were not all the same length. As a body-based unit, the foot ranged historically between about 250 and 335 millimeters, with ancient Greek and Roman feet near 300 mm. In medieval England a statute foot was set at 10/11 of an older Belgic foot, and Charlemagne's attempt around 790 to standardize units largely failed. The square foot is simply that length squared, so its size changed along with the foot.

The 1959 international agreement fixed the foot at exactly 0.3048 meter, so one square foot is exactly 0.09290304 m², or 144 square inches. The United Kingdom adopted the new foot in 1964. Today the square foot is the usual way of listing property in the United States, Canada, the United Kingdom, India, Pakistan, Singapore and Hong Kong, although the measuring convention varies: agents may measure corner to corner, subtract unheated space, or add heated space that extends beyond the end-to-end measurement. The world's smallest park has been reported at 2.6 sq ft.

1 square foot = 0.09290304 square meters (exactly).

Sources: Wikipedia: Square foot; Wikipedia: Foot (unit); NIST Guide to the SI, Appendix B.8: conversion factors

Acre (ac)

US & ImperialCurrent unit

43,560 square feet or exactly 4,046.8564224 m², about 40% of a hectare. Originally the area a yoke of oxen could plow in a day.

Ploughland gave the acre its name: it traces to Old Norse akr, meaning cultivated land, and is related to German Acker and Latin ager. In medieval England it was a farming measure, the land one man with a team of eight oxen could plough in a day. The traditional strip was 40 perches long and 4 perches wide, which is 660 by 66 feet, or ten square chains. The shape was never the point, and the article on the unit stresses that any area of 43,560 square feet is an acre.

An acre is 43,560 square feet, 4,840 square yards or 1/640 of a square mile, close to 0.4 hectare. For Americans, it is roughly 88 by 55 yards, about 90 percent of a football field without the end zones. The Weights and Measures Act 1878 fixed it at 4,840 square yards in Britain, where trade use ended in 1995. The 1959 international acre is exactly 4,046.8564224 m²; the US survey acre, about 4,046.872 m², differed slightly, and US survey units were retired after 2022.

1 acre = 4,046.856422 square meters (approximately).

Sources: Wikipedia: Acre; NIST Guide to the SI, Appendix B.8: conversion factors

Related conversions

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