Hectares
Abbreviation/Symbol:
ha
Unit of:
Worldwide use:
A hectare (ha) is 10,000 square meters, the area of a square 100m on each side, or 2.471 acres.
The hectare is not an SI unit, but it is accepted for use with SI. The name is the prefix hecto- (100) on the are, an older metric unit of 100 square meters, so a hectare is 100 ares.
To convert hectares to acres multiply by 2.47, so 40 hectares is about 99 acres. Going the other way, divide by 2.47.
Definition:
A hectare is 10,000 square meters, ie a square 100m by 100m, or 2.471 acres. The name is hecto-, a hundred, plus are, an older metric unit of 100 square meters. One square kilometer is 100 hectares.
Origin:
The hectare came in with the metric system after the French Revolution. It was defined as 100 ares, an are being a square 10 meters on each side.
The name joins hecto-, from the Greek for hundred, to are, from the Latin area. A hectare is therefore 100 ares, or 10,000 square meters – a square 100 meters on each side.
Common references:
Total area of the surface of the earth = 51 billion hectares
Area covered by earth's oceans = 36.2 billion ha
Usage context:
A hectare is 10,000 square meters – a square 100 meters on each side – and it is the standard unit for farmland and forests outside the US. One hectare is about 2.47 acres, so multiplying by 2.5 will do.
Another important usage context of hectares is in urban planning and real estate. City planners and developers use hectares to measure the size of land parcels, determine building densities, and assess the potential for development projects. Hectares are also used in zoning regulations and land-use planning to define the permissible uses and densities of different areas within a city or region.