Exponential Growth Calculator
Model exponential growth of populations.
About Exponential Growth Calculator
Doubling time for Exponential Growth shows how many periods it takes for a quantity to double at a fixed growth rate, which grows dramatically faster than it sounds. Exponential growth reaches large numbers quickly, so doubling time is the most intuitive way to grasp the pace.
Formula
Exponential Growth
Doubling time = 69.3 / rate%
- rule of 69
- Doubling time is roughly 69 divided by the percentage rate
Worked example
With the default values below, Exponential Growth Calculator returns Doubling Time of 13.86. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Growth rateaccepts 0–100 %
- 5 %
- Current populationminimum 0
- 1,000
- Number of periodsminimum 0
- 10
Results
- Doubling Time
- 13.86
- Future Population
- 1,629
- Growth Factor
- 1.629
Step by step
- 1Values used
- 2Exponential Growth
- 3Doubling Time= 13.86
- 4Future Population= 1,629
- 5Growth Factor= 1.629
Assumptions and limits
- The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax or fees or charges into account.
- Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is Exponential Growth calculated?
Doubling time = 69.3 / rate% Doubling time for Exponential Growth shows how many periods it takes for a quantity to double at a fixed growth rate, which grows dramatically faster than it sounds.
Why does Exponential Growth matter?
Exponential growth reaches large numbers quickly, so doubling time is the most intuitive way to grasp the pace.
What values do I need to enter?
This calculator takes 3 inputs: Growth rate, Current population, Number of periods. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.