What is the population density?
Type a population and its land area in square miles, square kilometers, acres, hectares or square meters. The population density calculator divides one by the other and shows people per square mile, per square kilometer and per acre.
- People per square mile
- 93.81
The population density is 93.81 people per square mile (36.22 per square kilometer).
- People per square kilometer
- 36.22
- People per acre
- 0.1466
- Land area in square kilometers
- 9,150,527.14
- Land area in square miles
- 3,533,038.28
People per square mile: 93.81. The population density is 93.81 people per square mile (36.22 per square kilometer).
How to calculate
Divides a population by its land area to give the population density in people per square mile and per square kilometer, from an area in any common unit.
Example with the default inputs (Population 331,449,281, Land area 3,533,038.28, Area unit Square miles): The population density is 93.81 people per square mile (36.22 per square kilometer).
Method: Density = population ÷ land area. Area is converted exactly: 1 sq mi = 2.589988110336 km², 1 acre = 0.0040468564224 km², 1 hectare = 0.01 km².
- The area is land area, as the Census Bureau uses; include water only if you mean to.
- You type both numbers; the page looks up no data.
Worked examples
Each example is checked against the calculator on every build.
- Population 331,449,281, Land area 3,533,038.28, Area unit Square miles gives People per square mile 93.814234, People per square kilometer 36.221878.Source: US Census Bureau QuickFacts, United States: population April 1, 2020 331,449,281; https://www.census.gov/quickfacts/note/POP060220
- Population 1,000,000, Land area 250, Area unit Square kilometers gives People per square kilometer 4,000, People per square mile 10,359.952441, Land area in square miles 96.52554.Source: https://www.census.gov/quickfacts/note/POP060220
- Population 500, Land area 200, Area unit Acres gives People per acre 2.5, People per square mile 1,600.Source: https://www.census.gov/quickfacts/note/POP060220
How it works
- The land area is converted to square meters with exact factors: 1 km² = 1,000,000 m²; 1 square mile = 1,609.344² = 2,589,988.110336 m²; 1 hectare = 10,000 m²; 1 acre = 43,560 square feet = 4,046.8564224 m². The mile and foot are the international ones (1 ft = 0.3048 m exactly); NIST's table rounds the square mile to 2.589 988 E+06 m² and also lists an older acre based on the US survey foot, which this page does not use.
- People per square mile = population ÷ (area in square miles).
- People per square kilometer = population ÷ (area in km²). It is the density per square mile ÷ 2.589988110336.
- People per acre = population ÷ (area in acres). A square mile is 640 acres.
- The page also shows the area in km² and in square miles.
Rules. The population is a whole number, 0 or more. The land area is at least 0.000001 in the chosen unit. The page looks up no data; you type both numbers.
Rounding. Every value is an exact fraction of the typed numbers, rounded once for display to 2 decimals (people per acre to 4 decimals).
Worked examples by hand
United States, 2020 (page default). Population 331,449,281; land area 3,533,038.28 square miles. 331,449,281 ÷ 3,533,038.28 = 93.81 per square mile; the Census Bureau shows 93.8. In km²: 3,533,038.28 × 2.589988110336 = 9,150,527.1 km², so 331,449,281 ÷ 9,150,527.1 = 36.22 per km².
A city. 1,000,000 people on 250 km². 1,000,000 ÷ 250 = 4,000.00 per km². 250 ÷ 2.589988110336 = 96.53 square miles, so 1,000,000 ÷ 96.5255 = 10,359.95 per square mile.
A neighborhood. 500 people on 200 acres. 500 ÷ 200 = 2.5000 per acre. 200 acres = 200 ÷ 640 = 0.3125 square miles, so 500 ÷ 0.3125 = 1,600.00 per square mile.
Other questions people ask
How do I calculate population density?
Divide the population by the land area. The United States had 331,449,281 people on 3,533,038.28 square miles of land in 2020: 331,449,281 ÷ 3,533,038.28 = 93.8 people per square mile.
How do I convert people per square mile to people per square kilometer?
Divide by 2.589988110336, the number of square kilometers in a square mile (or multiply by about 0.3861, as the Census Bureau notes). 93.81 per square mile is 36.22 per square kilometer.
Should I use total area or land area?
The US Census Bureau divides by land area, which leaves out lakes, rivers, coastal water and territorial seas. Using total area gives a lower density for places with a lot of water.
What is a high population density?
It depends on the scale. In 2020 the United States as a whole had about 94 people per square mile, while a dense city can have tens of thousands. Compare places of the same kind, such as counties with counties.
Why do two sources give different densities for the same place?
They may use a different population year, a different area (land or total), or a different boundary, such as a city limit or a metro area. Check all three before comparing.