Acres to Hectares (ac to ha)

1 acre equals 0.4046856422 hectares (rounded).

1 acre = 0.4046856422 hectares

How to convert acres to hectares

To convert acres to hectares, multiply the number of acres by 0.4046856422. The factor is rounded to 10 significant digits. To go the other way, multiply hectares by 2.471053815 (rounded).

hectares = acres × 0.4046856422

Example: 10 acres = 4.046856422 hectares.

About these units

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

Hectare (ha)

Metric (SI)Current unit

10,000 square meters (2.471 acres). The standard unit for land and agricultural areas outside the US.

Hecto plus are: the name was coined in French, and are itself comes from the Latin area, meaning an open space. The French law of 18 Germinal, Year III (7 April 1795) defined the are as 100 square meters, and the hectare followed as 100 ares, or 10,000 square meters. The unit is therefore a product of the original French metric reforms rather than of later SI work, which is one reason its official status has always been slightly awkward.

When the SI was set up in 1960 the are was not recognized, and the hectare was classed as a non-SI unit accepted for use with it. In practice it is the standard unit for land ownership, planning and agriculture in the European Union, the United Kingdom, Canada, Australia, New Zealand and South Africa, while the United States and Myanmar stay with the acre. A hectare is a square 100 meters on each side, about the size of Trafalgar Square, and equals roughly 2.47 acres. One hundred of them make a square kilometer.

1 hectare = 10,000 square meters (exactly).

Sources: Wikipedia: Hectare; Wikipedia: Are (unit); NIST Guide to the SI, Appendix B.8: conversion factors

Related conversions

See all area units.