# How do you calculate population growth?

##### 1 Answer

We calculate population growth by looking at the change in population over time.

#### Explanation:

We calculate population growth by looking at the change in population over time. The formula for population growth is below:

Learn about Euler's number here or here.

For example, if we have a population of zebras in 1990 that had 100 individuals, we know the population is growing at a rate of 5%, and we want to know what the population is in the year 2020, we would do the following to solve:

We multiply .05 by 30 years. Then we raise *e* by that result (1.5). Our last step is to then multiply 4.48 by our original population, which is 100 individuals.

Our answer is 448 individuals. So, from a population of 100 individuals in 1990, if that population is growing at a rate of 5%, we will have 448 individuals in the year 2020.