Rule of 72 Calculator
Quickly estimate how long it takes to double your money. The Rule of 72 gives a simple approximation based on your interest rate.
Financial Disclaimer
This calculator is for educational purposes only and does not constitute financial advice. Results are estimates based on the inputs provided. Consult a qualified financial advisor before making investment or financial planning decisions.
Inputs
Results
Years to Double (Rule of 72)
9 years
How to Use This Calculator
- Enter the annual interest or return rate for your investment (e.g., 8% for a diversified index fund).
- The calculator instantly shows years to double using the Rule of 72 (quick estimate) and the exact calculation.
- Optionally enter a starting amount to see the actual doubled dollar value.
- Review how many years to triple and quadruple your money as well.
- Use this to quickly compare investment options — a 4% savings account doubles in 18 years; a 9% investment doubles in just 8 years.
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