Population density calculator
This population density calculator divides the population by the area: 50,000 people living on 125 km² make a density of 400 people per km², or about 1,036 per square mile. It also works backwards and finds the population or the area from a given density.
Example: Calculate: Population density · Population 50,000 · Area 125 · Area unit: km² → Result: Population density: 400 people/km². Source: UN Statistics Division, Demographic Yearbook 2019, Technical notes Table 3: Dichte = Personen je km² Gesamtfläche (Land + Binnengewässer), Quadratmeilen × 2,589988, Dichte nur „an indication“ (gelesen 10.10.2026). Updated: .
How it is calculated
Population density = population ÷ area, usually in people per square kilometre. The UN Demographic Yearbook defines density as the number of persons in the total population per square kilometre of total surface area; Eurostat writes “the number of inhabitants per square kilometre”. For square miles the UN converts with 1 square mile = 2.589988 km², so a density per km² times 2.589988 gives the density per square mile.
Population density examples
| Population | Area in km² | People per km² |
|---|---|---|
| 50,000 | 125 | 400 |
| 120,000 | 48 | 2,500 |
| 2,500,000 | 800 | 3,125 |
| 1,000,000 | 2,590 | 386 |
| 8,000 | 2 | 4,000 |
The fourth row is an area of about 1,000 square miles: one million people there are 386 per km² or about 1,000 per square mile. The examples are calculated; for real places use the population and area published by the statistics office.
Working backwards
- Population = density × area: 400 people per km² on 125 km² are 50,000 people.
- Area = population ÷ density: 50,000 people at 400 per km² need 125 km².
- Hectares divide by 100 to get km² (100 ha = 1 km²).
What the number means
The UN points out that density gives only an indication of the actual density: it does not take into account how the population is spread or concentrated within a country, nor how much of the land is habitable. The area also matters. The UN uses total surface area including major rivers and lakes; Eurostat prefers land area without inland water wherever it is available. The same population can therefore give slightly different densities.
Square metres, hectares and acres convert with square meters to acres; for map distances use the map scale calculator, and for shares of a population the percentage calculator.
Frequently asked questions
How do you calculate population density?
Divide the population by the area. 50,000 people on 125 km² give 50,000 ÷ 125 = 400 people per km².
How do I convert density per km² to per square mile?
Multiply by 2.589988, the factor the UN uses for one square mile in km². 400 people per km² are about 1,036 people per square mile.
How do I find the population from the density?
Multiply the density by the area: 2,500 people per km² × 48 km² = 120,000 people.
Should lakes and rivers count in the area?
The UN Demographic Yearbook uses total surface area including inland waters; Eurostat prefers land area without inland water where it is available. Say which area you used.
Why can a high density be misleading?
Density is an average over the whole area. The UN notes it does not show whether people are concentrated in a few places or how much land is habitable.
Sources and legal basis
- UN Statistics Division, Demographic Yearbook 2019, Technical notes Table 3: Dichte = Personen je km² Gesamtfläche (Land + Binnengewässer), Quadratmeilen × 2,589988, Dichte nur „an indication“ (gelesen 10.10.2026)
- Eurostat, Statistics Explained – Glossary: Population density (Einwohner je km², möglichst Landfläche ohne Binnengewässer) (gelesen 10.10.2026)
As of: · Editorial policy
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