Determine the initial population size
Determine the final population size
Determine the time period between the two measurements
Subtract the initial population from the final population to find the change in population
Divide the change in population by the initial population
Divide the result by the number of time periods
Multiply by 100 to express the growth rate as a percentage
Use the formula: Growth rate = [(Final population – Initial population) / Initial population] / Time period × 100
If needed, calculate annual growth rate using the same formula with years as the time period
For repeated measurements, compare population sizes across equal time intervals