Statistics Definitions > Population Density

## Human Population Density

Population density is a statistic that tells you how many people live in a certain area. In general, pop. density is reported in square miles or kilometers, and may or may not include bodies of water. This type of measurement is called **arithmetic density**, and is reported as the total number of people per land area. For example, as of 2014, the Nile Delta has a pop. density of 1000 people per square kilometer. In other words, an average of 1000 people are living in an area 1 x 1 km.

### Formula

The formula for population density is:

number of people / square miles(or kilometers) of land.

The definition differs slightly according to which organization or entity is reporting the figure. For example:

- The World Bank defines population density as “midyear population divided by land area in square kilometers.” World Bank figures include all people living in a land area. This includes illegal aliens but excludes refugees (who are considered residents of their country of origin) and other temporary residents. “Land area” excludes major rivers and lakes.
- The University of Florida calculates population density by first excluding blocks of land where there are no people living (like parks, wetlands and forests). The university states that including this area (38% of Florida is completely uninhabited) can lead to misleading statistics about true population densities of where people actually live.

Apart from arithmetic density, less common types of pop. density measurement include:

**Residential density**: number of people living in urban areas / area of residential land.**Urban density**: number of people living in an urban area / area of urban land.**Agricultural density (also called physiological density)**: number of people in a rural area / area of arable land.

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