Glossary term
Population density
The number of people per unit of area — most commonly persons per square kilometre. Average density uses total land area; physiological density uses only arable land, giving a better sense of pressure on food-producing capacity. Both measures conceal significant internal variation, since human populations cluster dramatically rather than distributing evenly.
Density = Total population ÷ Land area (km²) Why average density is often misleading
A country's average density — total population divided by total land — is one of the most routinely misleading statistics in geography. Egypt has an average density of about 100 per km², but the entire population is effectively concentrated along the Nile Valley and Delta, which covers only about 4% of the country's land area. The effective density of inhabited Egypt is closer to 2,500 per km². Australia's official density of ~3 per km² obscures the fact that most Australians live in five coastal cities.
The NASA SEDAC Gridded Population of the World database produces spatially explicit population data at 1 km² resolution, allowing much more accurate depictions of where people actually live. The EU Global Human Settlement Layer provides similar data combined with built-up area extent.
Physiological density and resource pressure
Physiological density (also called nutritional density) uses only arable land — land capable of producing food — as the denominator. This gives a better measure of pressure on food-producing capacity. Egypt's physiological density is among the world's highest: over 3,000 per km² of arable land. Bangladesh's exceeds 1,500 per km² of arable land, representing one of the most intensively farmed agricultural systems on earth.
The FAO Land Resources data provides global arable land estimates by country. Physiological density is particularly relevant when considering food security — countries with very high physiological densities are most vulnerable to crop failure, climate impacts on agriculture, and soil degradation. See our analysis of climate migration projections where high-density, climate-exposed agricultural regions face the greatest displacement risk.
Density, urbanisation, and fertility
Population density interacts closely with urbanisation and fertility. High-density urban environments are associated with lower fertility — partly through higher housing costs, later marriage, and greater female labour force participation. This means the most densely populated urban cores typically have the lowest birth rates, even within high-fertility countries.
The relationship between national density and national fertility is more complex. Some high-density countries (Bangladesh, India) have high fertility; others (the Netherlands, Singapore) have low fertility. Density itself does not drive fertility — it is the urbanisation rate, income level, female education, and social norms that matter. Our World in Data provides interactive maps of population density alongside other demographic indicators for comparison.
Frequently asked questions
What is population density?
Population density is the number of people per unit of area — most commonly persons per square kilometre. The global average is approximately 60 per km². World Bank density data provides country-level figures.
Which countries have the highest and lowest population density?
Among large countries, Bangladesh (~1,280/km²) is the densest. Among city-states, Monaco (~19,000/km²) and Singapore (~8,000/km²) are extreme. At the other end, Mongolia (~2/km²), Namibia (~3/km²), and Australia (~3/km²) are the least dense. The NASA SEDAC gridded population database provides sub-national resolution.
Why is average density misleading?
Average density divides the entire land area equally, but populations cluster dramatically. Egypt averages ~100/km² but 95% of Egyptians live near the Nile — effective inhabited density exceeds 2,500/km². Gridded population databases from NASA SEDAC or the EU GHSL show where people actually live.
Does high population density cause problems?
Not necessarily. Singapore and the Netherlands are very dense and have high living standards. Density enables efficient infrastructure and economic agglomeration. Problems associated with density — congestion, housing costs, pollution — are often planning failures rather than density per se. High density in informal settlements without services creates acute health challenges — see our piece on World Urban Forum 2022.