Population Density Calculator
Determine how many people live per square kilometre in any region by dividing total population by land area. Useful for urban planners, geographers, and students comparing cities or countries.
About this calculator
Population density measures how concentrated a population is within a given area. The formula is: Population Density = Population / Area, where population is the total number of people and area is measured in km². The result is expressed as people per km² (persons/km²). High density values indicate crowded urban environments — Tokyo has a density above 6,000 people/km² — while rural regions may have fewer than 10 people/km². Population density is a key metric in urban planning, infrastructure allocation, healthcare resourcing, and environmental impact assessments. It is important to note that density is an average; actual distribution within an area may be highly uneven, with dense city centres and sparse outskirts.
How to use
Bangladesh has a population of approximately 170,000,000 people and a land area of about 147,570 km². Enter Population = 170,000,000 and Area = 147,570. The calculator computes: Population Density = 170,000,000 / 147,570 ≈ 1,152 people/km². This makes Bangladesh one of the most densely populated countries in the world. For comparison, Australia with roughly 26,000,000 people over 7,692,024 km² has a density of just 3.4 people/km².
Frequently asked questions
What is considered a high population density for a city or country?
There is no universal threshold, but densities above 1,000 people/km² are generally considered high for a country, while city districts can easily exceed 10,000–20,000 people/km². Singapore and Bangladesh rank among the densest nations at over 1,000 people/km², while Monaco tops the list at over 26,000 people/km². In contrast, countries like Mongolia or Australia average fewer than 5 people/km². Context matters: a 500 people/km² figure is very dense for a rural province but sparse for a city centre.
How is population density used in urban planning and infrastructure decisions?
Urban planners use population density to determine where to invest in roads, public transit, schools, hospitals, and utilities. High-density areas justify expensive infrastructure like metro rail systems because the cost is spread across many users. Low-density areas may be better served by buses or private vehicles. Density thresholds also inform zoning laws — minimum density requirements can encourage transit-oriented development, while caps prevent overcrowding of existing infrastructure. Water and sewage capacity planning also relies directly on density projections.
Why can population density be misleading when comparing regions?
Population density is an average that can obscure significant internal variation. A country with a vast uninhabitable desert and a small fertile region will show a low average density even though its habitable areas are extremely crowded. Similarly, a city's administrative boundaries may include large parks or industrial zones that dilute the apparent density. Analysts often use 'physiological density' — population divided by arable land only — to better reflect true human pressure on livable space.