Acres to Square Feet Calculator

Background.

A listing gives a lot's size in acres, while the zoning code sets its minimums in square feet and the builder prices work per square foot. Moving between them takes one multiplication, because the acre is defined in feet: one acre is exactly 43,560 square feet. That is the area of a strip one chain wide (66 feet) and one furlong long (660 feet), the old surveying units the acre was built from, so nothing is measured or rounded along the way.

An acre has no set shape, which is why it is hard to picture. Laid out as a square it would be about 208.7 feet on each side. An American football field, end zones included, is 360 by 160 feet, or 57,600 square feet — roughly 1.32 acres.

The square-meter figure is there for metric site plans and for comparison with hectares. Since 1959 the foot has been exactly 0.3048 meters, so a square foot is exactly 0.09290304 m² and an acre is exactly 4,046.8564224 m², a little over four-tenths of a hectare.

What is acres to square feet calculator?

An acre is a unit of land area equal to exactly 43,560 square feet, which is the same as 4,840 square yards or 10 square chains; 640 of them make a square mile. It is defined by area alone, so a long narrow strip and a neat square can both be one acre. The acre remains the everyday unit for land in the United States and is still widely used informally in Britain.

How to use this calculator.

1. 01Enter the acreage from the deed, survey or listing. Fractions go in as decimals, so a lot listed as 2½ acres is 2.5.
2. 02Read square feet for zoning minimums, lot-coverage limits and anything priced per square foot, and square meters for metric drawings.
3. 03If a boundary or compliance decision depends on the result, start from the surveyed acreage rather than a rounded figure from a listing; the conversion itself adds no error.

The formula.

Square feet = acres × 43,560, and square meters = acres × 4,046.8564224. The first constant is the definition of the acre: 66 ft × 660 ft = 43,560 ft². The second follows from the international foot of exactly 0.3048 m. Squaring it gives 0.09290304 m² per square foot, and 43,560 × 0.09290304 = 4,046.8564224 m². Both constants are exact by definition, so the only uncertainty in either answer is whatever was already in the acreage you started from. Dividing the square-meter result by 10,000 gives hectares.

A worked example.

Frequently asked questions.

References& sources.

1. [1]National Institute of Standards and Technology (2008). NIST Special Publication 811: Guide for the Use of the International System of Units (SI), Appendix B — Conversion Factors. Source for the statutory 43,560 ft² acre (1 chain x 1 furlong) and its exact metric equivalent.
2. [2]National Institute of Standards and Technology. SI Units — Length — the international foot is exactly 0.3048 meters, fixed by the 1959 international yard-and-pound agreement.