Rule of 72 Calculator
Enter an annual interest rate to estimate how many years it takes to double your investment using the Rule of 72 — a quick mental math shortcut.
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Years to Double
Enter values to calculate
How to Use the Rule of 72 Calculator
1
Enter the annual interest rate.
2
Click Calculate.
3
View the estimated years to double your money.
Frequently Asked Questions
What is the Rule of 72?
Years to Double = 72 / Interest Rate. At 6% interest, your money doubles in approximately 12 years.
How accurate is this rule?
It is most accurate for rates between 6-10%. For very high or low rates, the actual time may differ slightly.
Does it work for inflation too?
Yes — 72 / inflation rate tells you approximately how many years until prices double.