The square kilometre (square kilometer in American spelling; symbol: km<sup>2</sup>) is a multiple of the square metre, the SI unit of area or surface area. In the SI unit of area (m<sup>2</sup>), 1 km<sup>2</sup> is equal to 1M(m<sup>2</sup>).
1 km<sup>2</sup> is equal to:
- 1,000,000 square metres (m<sup>2</sup>)
- 100 hectares (ha)
It is also approximately equal to:
- 0.3861 square miles
- 247.1 acres