Square kilometre

Square kilometre (U.S. spelling: square kilometer), symbol km², is an SI unit of surface area. It is one of the SI derived units.

1 km² is equal to:
*the area of a square measuring 1 kilometre on each side
*1 000 000 m²
*100 hectares
*0.386 102 square miles (statute)
*247.105 381 acres

Conversely:
*1 m² = 0.000 001 km²
*1 hectare = 0.01 km²
*1 square mile = 2.589 988 km²
*1 acre = 0.004 047 km²

Note: "km²" means square kilometre and not kiloâ€"square metre. For example, 3 km² is equal to 3 000 000 m², not 3000 m².

Comparative order of magnitude

The 1 E6 m² orders of magnitude page gives comparisons with geographic areas.

hectare (10⁴ m²) < square kilometre < square megametre (10¹² m²)

See also

*Conversion of units.
*SI prefix for the precise meaning of the prefix "k"