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Population Growth Rate- Definition, Formula, Factors, and Importance

May 23, 2023
written by Sidra Batool

Population growth rate refers to the rate at which the population of a particular species increases or decreases over a given period. It is an important concept in ecology and population Biology because it helps scientists understand the dynamics of population change and the factors that influence it.

The population density, population distribution, and population size together provide insights into the particular arrangement and scale of a given population.

How to Find Population Growth Rate?

Population growth rate can be positive, negative, or zero. A positive population growth rate means that the population is increasing, while a negative population growth rate means that the population is decreasing. A zero population growth rate means that the birth rate is equal to the death rate, resulting in no net change in population size.

Population Growth Rate Formula

To calculate the population growth rate (GR), we follow a simple equation:

GR = ((Population at Time 1 – Initial Population) / Initial Population) x 100


  • GR represents the population growth rate
  • Population at Time 1 refers to the population at a later time, and Initial Population represents the population at the starting point.

Example of Population Growth Rate

Let’s say we have a small village called “Sunnyville” with an initial population of 500 people. We’ll assume a constant annual growth rate of 2%.

To calculate the population of Sunnyville after a certain number of years, we can use the following formula:

Population = Initial Population * (1 + Growth Rate)^Number of Years

Now, please enter the number of years you want to calculate the population for: 5

After 5 years, the population of Sunnyville would be:

Population = 500 * (1 + 0.02)^5
Population = 500 * (1.02)^5
Population ≈ 500 * 1.10408
Population ≈ 552.04

Therefore, after 5 years, the population of Sunnyville would be approximately 552.

Factors Affecting Population Growth Rate

Population growth rate can be influenced by various biotic and abiotic factors that affect the birth and death rates of a population. Some of the primary factors include:

1.      Reproductive Rate

The rate at which individuals reproduce, which can significantly influence population growth rate. High reproductive rates can lead to rapid population growth, while low reproductive rates can result in slower population growth.

2.      Availability of Resources

The availability of essential resources such as food, water, shelter, and suitable habitat plays a vital role in supporting population growth. Limited resources can limit population size and growth.

3.      Competition

Competition for limited resources among individuals within a population can affect population growth rate. Intense competition can result in reduced birth rates and increased death rates.

4.      Predation

The presence of predators can influence population growth rate by reducing the number of individuals through predation, which can impact population size and growth.

5.      Disease and Health

The prevalence of diseases and overall health status within a population can significantly impact population growth rate. Disease outbreaks can increase death rates, leading to a decline in population size.

6.      Environmental Factors

Physical factors such as climate, temperature, precipitation, and availability of sunlight can influence population growth by affecting the suitability of the environment for individuals to survive and reproduce.

7.      Migration and Dispersal

The movement of individuals into or out of a population can impact population growth rate. Migration and dispersal can introduce new individuals or reduce population size in a particular area.

8.      Genetic Diversity

Genetic diversity within a population is essential for adaptation and resilience. Higher genetic diversity can enhance population growth by providing a greater potential for adaptation to changing environments.

9.      Carrying Capacity

The maximum number of individuals an ecosystem can sustainably support over the long term. Population growth may be influenced by how close the population is to or exceeds the carrying capacity of the environment.

10.  Human Impact

Human activities, such as deforestation, pollution, habitat destruction, and resource exploitation, can have significant effects on population growth rates of various species, including humans, animals, and plants.

Importance of Population Growth Rate

Population growth rate is an essential concept in ecology and population biology, because by understanding the factors that influence population growth rate, scientists can develop strategies to conserve and manage populations of different species.

For example, conservationists can use population growth rate data to identify populations at risk of decline and prioritize conservation efforts.


Why do we calculate growth rate?

Population growth rate refers to the annual average rate of change in the size of a population within a specific country, territory, or geographic area over a defined period of time.

What factors contribute to population growth rate?

Following factors are involved in population growth rate:
Birth rate
Death rate
Healthcare and medicine
Socioeconomic factors
Government policies
Cultural and religious beliefs
Economic development
Social and gender equality
Environmental factors

which country has the highest population growth rate?

The country with the highest population growth rate are:
Syria: 6.39%
South Sudan: 4.78%
Niger: 3.66%