About the Rule of 72 Calculator
Estimate how many years it takes for money to double at a given rate. This tool is free, works in your browser and needs no sign-up.
How to use the Rule of 72 Calculator
Enter the yearly rate of return. The tool shows the quick Rule of 72 answer and the exact answer.
Formula used
Years to double ≈ 72 ÷ rate. Exact years = ln 2 ÷ ln(1 + rate).
Example
With Rate of return (% per year) 8, the calculator shows: Years to double (Rule of 72) = 9.0; Exact years to double = 9.0; Years to triple (Rule of 114) = 14.3.
Frequently asked questions
Is the Rule of 72 Calculator free to use?
Yes. It is completely free and you can use it as many times as you like.
How accurate is the Rule of 72 Calculator?
The calculator uses standard formulas, so the maths is exact. Real life results can differ because of fees, taxes, rounding or personal factors, so treat the answer as an estimate.
Do you store the numbers I enter?
No. All calculations run in your browser. The values you type are not sent to our server.
Disclaimer: results are estimates for information only. They are not financial, medical or professional advice.