Article: To calculate the population density, you will divide the population by the size of the area. Thus, Population Density = Number of People/Land Area.  The unit of land area should be square miles or square kilometers. You can use square feet or meters if you are finding the density of a smallish space. For most professional and academic demographic purposes, though, you'll need to use the standard square miles or kilometers. The unit of population density is people per unit of area. For instance, 2000 people per square mile. You should know the population and the surface area of the region. For example: if there are 145,000 people in the city of Auburn, and the urban area covers 9 square miles, write 145,000/9 square miles. Use long division, or just use a calculator. In our example, 145,000 divided by 9 would show that the population density is 16,111 people/square mile.

What is a summary?
Learn the formula. Plug your data into the formula. Divide the population by the area size.