Calculate doubling time from a growth rate, and the growth it produces over a period.
Doubling time comes from the logarithmic form of compound growth. The rule of 70 approximates it well at low rates and drifts upward as rates rise above about 15 per cent. Doubling time is the most intuitive way to convey exponential growth, whether for bacteria, compound interest or data volumes.
Doubling Time
t_double = ln2 ÷ ln(1 + r); rule of 70: t ≈ 70 ÷ growth percentage
t_double = ln2 ÷ ln(1 + r); rule of 70: t ≈ 70 ÷ growth percentage Doubling time comes from the logarithmic form of compound growth. The rule of 70 approximates it well at low rates and drifts upward as rates rise above about 15 per cent.
Doubling time is the most intuitive way to convey exponential growth, whether for bacteria, compound interest or data volumes.
This calculator takes 3 inputs: Growth rate per period, Number of periods, Initial quantity. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.