# Square kilometre

decimal multiple of the SI unit of surface area

A square kilometer (British English spelling square kilometre, in short km²) is a unit of measurement of area. It is based on the SI unit meter.

## Equal areas

A square that has a side length of 1 kilometer (1000 meters) has an area of one square kilometer.

1,000 m × 1,000 m = 1 km × 1 km = 1,000,000 m² = 1 km²

There are 100 hectares in one square kilometer. One square kilometer is just less than 0.39 square miles.

## Use

Square kilometer is often used to say how much surface something occupies on Earth. It can, for example, be used to describe the area of a city or country. These usually take more than 1 km² on Earth.

The number of people living in a square kilometer is known as population density.

## Sources

1. "Common Weights and Measures". The Columbia Electronic Encyclopedia (6th ed.). Columbia University Press. January 24, 2017. Retrieved April 21, 2023.
2. "15 Questions About Units of Measurement Answered". Encyclopaedia Britannica. August 26, 2021. Retrieved April 21, 2023. There are 100 hectares in 1 square kilometer […]