How to Calculate Population Growth Rate in Percentage

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Population Growth Rate Calculator

Initial Population (Start Year)

Current / Final Population (End Year)

Time Period (Years) Enter 1 if calculating simple growth between two points in time without annualizing.

Please enter valid positive numbers. Initial population cannot be zero.

Absolute Population Change 0

Total Percentage Growth 0.00%

Average Annual Growth Rate (CAGR) 0.00%

Understanding demographics is crucial for urban planning, resource allocation, and economic forecasting. One of the most fundamental metrics in this field is the population growth rate. This percentage tells us how fast a population is increasing or decreasing over a specific period, allowing for comparisons between different cities, countries, or timeframes regardless of their size.

The Basic Formula

To calculate the population growth rate in percentage, you compare the change in population relative to the initial population size. The standard formula is:

Growth Rate (%) = ((P_end – P_start) / P_start) × 100

Where:

P_end: The population at the end of the period.
P_start: The population at the beginning of the period.

Step-by-Step Calculation Example

Let's calculate the growth rate for a hypothetical town, "Springfield".

Determine the Start Population: In 2018, Springfield had 15,000 residents.
Determine the End Population: By 2023, the population grew to 18,500.
Find the Difference: 18,500 – 15,000 = 3,500 (This is the absolute growth).
Divide by the Start Population: 3,500 / 15,000 = 0.2333…
Convert to Percentage: 0.2333 × 100 = 23.33%

In this example, Springfield experienced a total population growth of 23.33% over the 5-year period.

Annual Growth Rate (CAGR)

While the total percentage tells you how much the population grew overall, it is often more useful to know the Annual Growth Rate, especially when comparing periods of different lengths. This is often calculated as the Compound Annual Growth Rate (CAGR).

The formula for annual growth is:

Annual Rate (%) = ((P_end / P_start)^(1/t) – 1) × 100

Using the Springfield example with t = 5 years:

((18,500 / 15,000)^(1/5) – 1) × 100 ≈ 4.28% per year.

Factors Influencing Population Growth

When analyzing these percentages, it is important to understand the components that drive the numbers:

Natural Increase: The difference between the number of live births and the number of deaths.
Net Migration: The difference between the number of immigrants (people moving in) and emigrants (people moving out).

A positive percentage indicates growth, while a negative percentage indicates a population decline (shrinkage). Use the calculator above to quickly determine these metrics for your specific data sets.