Need an easy way to determine how long it will take to double your investment? The rule of 72 provides a simple estimate of the number of years it will take an investment to double given a fixed rate of return.
To use the rule, divide 72 by your annual estimated rate of return. The result is the number of years it will take for your money to double.
As with most tools, however, the rule of 72 has its limitations. It’s an approximate result that becomes less accurate as the rate of return increases.