Choose population density, population, or land area, then enter the two values requested. Area and density units include square kilometers, square miles, hectares, acres, square meters, square feet and square yards.

Use population and land area for the same boundary and reference date.

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Population Density Formula

The following equation can be used to calculate the population density of an area.

D = P / A

Formula source:  U.S. Census Bureau – Understanding Population Density

  • Where D is the density
  • P is the population number
  • A is the area

In the case of population density, we use a total number of people per unit area. Normally in math, density is a mass or number per unit volume. When analyzing populations, volumes don't make much sense to look at, so we use area.

Population Density Definition

Population density is the total population divided by the land area of the same geographic boundary. Use matching reference dates; this average does not describe variation within the area.

Population Density Example

How to calculate population density?

The following example problem outlines the steps required for calculating a population density.

First, determine a specific area to analyze. This arithmetic example uses an illustrative city boundary.

Assume this example city has 8,419,000 people. This is an illustrative input, not a current or verified historical New York City population estimate.

Next, use a land area of 302.6 square miles for the same example boundary.

Finally, calculate the population density: D = P/A = 8,419,000 / 302.6 ≈ 27,822.21 people per square mile.

Population Density Units

In most cases, population density is expressed as the number of people per square mile, or the number of people per square kilometer.

For a different denominator unit, convert the area consistently. The calculator uses the international foot: 1 square mile = 2.589988110336 square kilometers = 640 acres. Display settings control decimal places and thousands separators.

6 Things to Know About Population Density

1. Why is population density important?

Population density is a key metric in understanding not only the economics and logistics involved in an area but also the culture and the mindset of the people living there.

One example of this importance can be seen in urban planning. When engineers design bridges, sewage, and other infrastructure for areas, one of the essential design considerations is population density.

Knowing the population density allows the engineer to design the infrastructure to handle that population or rate of usage the infrastructure would see. Without this critical information, the engineer may design something that could fail under heavier-than-expected usage.

2. Can population density change?

A population density will change when the number of people living in an area increases or decreases.

If the population increases in an area, the population density will also increase. If the population decreases, the density will also decrease. This means that the population and density are directly dependent on one another. This can be seen from the equation above.

Another uncommon way population density can change is if the borders of an area are changed legally.

For example, if a town had an initial area of 20 square miles, but after some litigation, the town agrees to include another 1-square-mile area in their borders, then the population density will change.

3. Does population density affect temperature and climate?

Population density alone does not determine temperature or global climate impacts.

Local urban heat depends on land cover, building materials and geometry, vegetation, weather and waste heat; a population-density calculation does not model these factors.

The U.S. EPA explains that built surfaces absorb and release heat, reduced vegetation limits cooling, and human activities add heat. Urban temperature is not a universal function of population density.

4. What population density levels are considered urban and what levels are considered rural?

There is no universal density cutoff. Under the U.S. Census Bureau’s 2020 criteria, qualifying territory must meet detailed density and development criteria and contain at least 2,000 housing units or 5,000 people. Rural territory is outside the delineated urban areas. The calculator does not assign an official classification.

5. What are the effects of low population density?

Having a low population density has both benefits and downsides.

Lower density may reduce crowding or congestion in some settings, but land prices, pollution and access to food also depend on local markets, transport and land use.

Potential challenges include longer travel distances and more dispersed infrastructure. Productivity, wages and community characteristics cannot be inferred from density alone.

These effects do not simply reverse at high density; local conditions and policy matter.

6. Where is population density the highest?

Density rankings depend on the reference year and whether the boundary represents a municipality, urban area, metropolitan region or neighborhood. Comparing unlike boundaries does not establish a reliable world ranking.

Use consistent geographic definitions and reference dates when comparing places; the calculator does not identify a most densely populated place.