Doubling Time Calculator
Calculate doubling time for exponential growth. Enter growth rate to find doubling time, or enter time to find required growth rate.
Calculate Doubling Time from Growth Rate
Calculate Growth Rate from Doubling Time
Common Doubling Time Examples
5% growth
→
14.21 periods
(Rule of 72: 72÷5=14.4)
10% growth
→
7.27 periods
(Rule of 72: 72÷10=7.2)
15% growth
→
4.96 periods
(Rule of 72: 72÷15=4.8)
20% growth
→
3.80 periods
(Rule of 72: 72÷20=3.6)
How to Calculate Doubling Time
Formula
Doubling Time = log(2) ÷ log(1 + growth_rate)
Rule of 72 (Approximation)
For quick estimation: Doubling Time ≈ 72 ÷ growth_rate
This rule works well for growth rates between 6% and 10%.
Applications
- Finance: Investment growth, compound interest
- Population: Population growth, bacteria growth
- Economics: GDP growth, inflation
- Biology: Cell division, population dynamics
Examples
- 5% annual growth: log(2) ÷ log(1.05) = 14.21 years
- 10% annual growth: log(2) ÷ log(1.10) = 7.27 years
- 15% annual growth: log(2) ÷ log(1.15) = 4.96 years