Rule of 72 Calculator
Estimate how many years it takes to double your money, or the rate needed for a target timeframe.
Years to double
9 years
Required rate
7.2%
A quick mental-math shortcut for investing. Enter an interest rate to see years to double, or a target number of years to see the required rate.
How to use
- Enter an annual interest rate to see years to double.
- Enter a target number of years to double your money.
- Read the interest rate required to hit that target.
Frequently asked questions
- What is the Rule of 72?
- It is a shortcut that estimates years to double an investment by dividing 72 by the annual rate of return.
- How accurate is it?
- It is a close approximation for rates between roughly 6% and 10%, and less precise for very high or very low rates.