How to use the Rule of 72 Calculator
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Formula
Years to double ≈ 72 ÷ annual return %
Exact = ln(2) ÷ ln(1 + r)
Frequently asked questions
How accurate is the Rule of 72?
Very close for returns between 6% and 10%. It becomes less accurate at very high or low rates.
Results are estimates for information only and are not financial, tax or legal advice. Tax rules, interest rates and fees change, so confirm important numbers with your bank, employer or a qualified adviser. Read our disclaimer.