Rule of 72 Calculator
Quickly estimate how many years it takes to double your money at a given interest rate.
Assumptions used in this calculation
- Approximation: The Rule of 72 is a mental-math shortcut, most accurate for interest rates roughly between 6% and 10%.
About this calculator
The Rule of 72 calculator gives a quick mental-math estimate of how many years it takes an investment to double, by dividing 72 by the annual interest rate.
Worked example
8% interest
Result: 9 years to double
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