Ecology & populations · SL/HL
Population Growth Rate Calculator
Enter initial and final population estimates and elapsed time.
Your values
Start with the example or enter your own values. Use a dot for decimals and e for scientific notation.
Calculated locally. No account or input upload.
Result & working
ExampleThe calculator is loading. The worked example is also shown below.
Step-by-step working
The formula
ΔN = N₂ − N₁
average growth rate = ΔN/Δt
percentage change = ΔN/N₁ × 100%
| Symbol | Meaning |
|---|---|
| N | Population size. |
When to use this calculator
This is an average over the interval, not an instantaneous logistic-growth model.
Worked example
The page opens with these example values. The result below is pre-generated for reference.
- ΔN = 1500 − 1200 = 300
- average rate = ΔN/Δt = 300/3 = 100 per years
- percentage change = 300/1200 × 100 = 25%
100 individuals/years
Common mistakes
- A percentage increase and an absolute increase answer different questions.