Question: How is population density calculated? Need Assignment Help? Question Answer Population density is calculated as the number of reproducing individuals from a population divided by the size of the habitat. Population density is calculated as the total number of all organisms, plants and animals, found in a given area or volume. Population density is calculated as the total number of organisms of a species found in an area divided by the size of the habitat. Population density is calculated as the number of species in a habitat and represents the total biomass for a unit area.