Square Centimeters to Acres (cm² to ac)

1 square centimeter equals 2.471053815×10⁻⁸ acres (rounded).

1 square centimeter = 2.471053815×10⁻⁸ acres

How to convert square centimeters to acres

To convert square centimeters to acres, multiply the number of square centimeters by 2.471053815×10⁻⁸. The factor is rounded to 10 significant digits. To go the other way, multiply acres by 40,468,564.22 (rounded).

acres = square centimeters × 2.471053815×10⁻⁸

Example: 10 square centimeters = 2.471053815×10⁻⁷ acres.

About these units

Square Centimeter (cm²)

Metric (SI)Current unit

A square one centimeter on a side; 1/10,000 of a square meter.

Physicists, rather than surveyors, put the centimeter at the center of a measuring system. Carl Friedrich Gauss proposed absolute units based on length, mass and time in 1832, choosing the millimeter, and in 1873 a British Association committee including James Clerk Maxwell and William Thomson (Lord Kelvin) recommended the centimeter, gram and second instead. In that CGS system the square centimeter turns up inside derived units, such as the stokes of kinematic viscosity, defined as one square centimeter per second.

A square centimeter is one ten-thousandth of a square meter, so 10,000 of them fill a square meter. It is a natural size for small flat things: a square inch is exactly 6.4516 cm², and a square foot is exactly 929.0304 cm². Because the CGS system defined force and pressure with the centimeter, the dyne per square centimeter became its unit of pressure, called the barye, which equals 0.1 pascal. SI practice prefers the square meter for large areas and the square millimeter for very small ones.

1 square centimeter = 0.0001 square meters (exactly).

Sources: Wikipedia: Centimetre-gram-second system of units; Wikipedia: Square centimetre; 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

See all area units.