Rule of 72 Calculator - Free, Instant, In Your Browser
Enter an annual interest rate (as a percentage) to estimate the years needed to double your money.
How to use Rule Of 72 Calculator
- 1Paste your text or data into the input box above.
- 2Rule Of 72 Calculator runs instantly, right in your browser.
- 3Copy the result or use it directly.
Your file is processed in your browser and is never uploaded.
Frequently Asked Questions
What's the formula?
Years to double ≈ 72 / annual interest rate - a well-known mental-math shortcut, most accurate for rates between about 6% and 10%.
Is my data sent to a server?
No - everything runs entirely in your browser with JavaScript. Nothing is uploaded.