Enter the annual rate of return.
Formula
Years to double ≈ 72 / rate (%)
Worked example
At 6% a year, money doubles in about 72 / 6 = 12 years (exact: 11.9).
Frequently asked questions
How accurate is the rule of 72?
Very close for rates between about 4% and 12%.
Does it work for inflation?
Yes: at 3% inflation, prices double in about 24 years.
What is the rule of 70?
A variant that is slightly more accurate for low rates.
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Results are estimates for information only. Check important figures with a professional.