Square kilometer (km²)
Definition
One million square meters (10⁶ m²).
History
The square kilometer is a square one kilometer on each side, one million square meters. It became the metric unit for large land areas.
Where it is used
Square kilometers measure land area and the size of cities and regions.
Typical uses include land area, city and region sizes.
Conversion pages
These pages convert square kilometer to or from another unit in area.
No conversion pages use this unit yet.
Other Area units
Sources
- BIPM SI BIPM SI Brochure (2019) · Dataset reviewed Nov 11, 2026