How to Use Rule of 72 Calculator
Estimate how long it takes an investment to double, or the rate needed to double it.
Open the Rule of 72 Calculator tool →What is Rule of 72 Calculator?
Estimate how long it takes an investment to double, or the rate needed to double it. It's completely free, needs no sign-up, and runs entirely in your browser — so it's fast and private.
How to use Rule of 72 Calculator
- Open the Rule of 72 Calculator tool.
- Enter your details or values.
- The result is calculated instantly.
- Copy or use the result. Everything runs in your browser — nothing is uploaded.
Frequently asked questions
What is the Rule of 72?
A shortcut: divide 72 by the annual return to estimate the years for money to double (e.g. 72 ÷ 8% ≈ 9 years).
How accurate is it?
It's an approximation, most accurate for rates around 6-10%. For exact figures, use a compound interest calculator.
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