Rule of 72
A quick mental-math shortcut to estimate how many years it takes to double an investment.
Calculator
Rule of 72
Time to Double = 72 / Rate
%
1%25%
Time to double (rule of 72)6.0 years
Exact calculation6.12 years
Approximation error0.12 years
How to use this
Divide 72 by the annual rate of return. The result is the approximate number of years to double your money. The calculator also shows the exact answer for comparison.
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