Population Growth Rate Calculator
Calculate the annual and total percentage growth of any population over a specific period.
How to Calculate Population Growth Rate
Understanding population growth is essential for urban planners, ecologists, and government agencies to allocate resources, build infrastructure, and protect environments. The growth rate represents the fractional change in a population over a specific time interval.
Geometric vs. Linear Growth
Most biological populations do not grow linearly; they grow geometrically or exponentially because the existing population reproduces. Our calculator uses the Geometric Growth formula by default, which is more accurate for multi-year trends:
Where:
- P_initial: The population at the start of the period.
- P_final: The population at the end of the period.
- t: The number of years between measurements.
- r: The annual growth rate.
Practical Example
Suppose a town had 10,000 residents in 2010 and grew to 15,000 residents by 2020. To find the growth rate:
- Initial Population = 10,000
- Final Population = 15,000
- Time = 10 years
- Total Increase = 5,000 (50%)
- Annual Geometric Growth Rate = 4.14%
What is the Doubling Time?
The doubling time is a frequent metric used in demographics. It uses the "Rule of 70" for a quick estimate, or a logarithmic formula for precision. It tells you how many years it will take for the current population to double if the growth rate remains constant.