Non-SI unit accepted for use with SI
Name Symbol Quantity Value in SI units
hectare ha area 1 hm2
104 m2


The hectare, symbol ha, is a non-SI unit of area accepted for use with the SI.
One hectare is equal to one square hectometre, symbol hm2, or 10 000 m2.

Originally one hectare meant 100 ares, where one are was a unit equal to 100 m2. The are is now obsolete, but the hectare remains as a unit accepted for use with the SI.

The hectare is used mostly as a unit to express land areas. There are 100 hectares in one square kilometre.

The non-SI unit hectare, symbol ha, is equal in size to the SI unit square hectometre, symbol hm2.

1 ha = 10 000 m2 = 1 hm2
100 ha = 100 hm2 = 1 km2

Note: SI prefixes must not be used with the hectare.