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Rule of 72 Calculator
A quick mental-math tool for understanding the relationship between return and doubling time.
Enter your numbers and select Calculate.
What this calculator helps you understand
Use the Rule of 72 to estimate how long an investment could take to double at an assumed annual return. The goal is to make the financial concept easier to understand by letting you test different scenarios rather than relying on a single example.
How to use it
- Enter numbers that match your situation.
- Change one assumption at a time and compare the result.
- Use the result as an estimate, not a guarantee.
Important: This is an educational calculator. Actual results can differ because of rates, taxes, fees, plan rules, market performance, lender terms and other circumstances.
Frequently asked questions
What is the Rule of 72?
It is a shortcut that estimates doubling time by dividing 72 by an annual percentage return.
Is it exact?
No. It is a rule of thumb and becomes less precise at extreme rates.
Does it include taxes and fees?
No. It ignores taxes, fees and changes in returns.
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