Example: Annual return: 8% → Years to double your money: 9.
Doubles in 20 years: 4.7× (approx.)
Frequently asked questions
How do I calculate rule of 72? Enter your numbers above and the result updates instantly. For example: Annual return: 8% → Years to double your money: 9.
Is this Rule of 72 Calculator free? Yes — completely free with no sign-up or paywall. It runs entirely in your browser and keeps working offline; the numbers you enter never leave your device.
How accurate is it? It uses the standard published formula for rule of 72. Results are estimates for planning — not financial, tax, medical, engineering, or legal advice.