Square kilometre (US 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

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

hectare << square kilometre << square megametre

See also

• Conversion of units.