Rule of 72 Calculator
How long it takes money to double.
Your numbers
Years to double (rule of 72)
9
Exact years to double
9.01
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Save your current numbers, change them, save again, and see each estimate side by side. Saved in this browser only.
How it works
Divide 72 by the annual return. The exact answer uses ln(2) ÷ ln(1 + r).
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Results are estimates for education only and are not investment advice.