Population Doubling Calculator

Calculate doubling time from a growth rate.

About Population Doubling Calculator

Doubling time for Population Doubling 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

Population Doubling

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, Population Doubling 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
2Population Doubling
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 Population Doubling calculated?

Doubling time = 69.3 / rate% Doubling time for Population Doubling 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 Population Doubling 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.