Rule of 72 Calculator
Quickly estimate how many years it takes to double your money at a given rate of return. Includes both the Rule of 72 approximation and exact calculation.
About the Rule of 72 Calculator
The Rule of 72 is a simple mental math shortcut: divide 72 by your annual return rate to estimate how many years it takes for your investment to double. This calculator shows both the Rule of 72 estimate and the exact logarithm-based result.
Example: At 8% return — Rule of 72 says ~9 years to double (exact: 9.01 years).
How to use: Enter your expected annual return rate. Both the Rule of 72 approximation and exact result appear instantly.
Disclaimer: This calculator is for informational purposes only. Results are estimates and should not be considered financial advice. Verify important calculations independently.