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Rule of 72
Estimate how many years it takes for an investment to double at a given annual return rate, using the classic Rule of 72.
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About the Rule of 72
What is it?
The Rule of 72 is a quick mental math shortcut to estimate how many years it takes for an investment to double at a fixed annual rate. Simply divide 72 by the annual return percentage.
When to use
Use it to quickly compare investment options, understand the power of compound interest, or assess whether a rate of return aligns with your financial goals.
When NOT to use
Do not rely on it for precise financial planning or when interest compounds at non-annual intervals. For accurate projections use a full compound interest calculator.