Investopedia contributors come from a range of backgrounds, and over 25 years there have been thousands of expert writers and editors who have contributed. Robert Kelly is managing director of XTS ...

The rule of 72 is a shortcut investors can use to determine how long it will take their investment to double based on a fixed annual rate of return. To use the rule of 72, divide 72 by the fixed rate ...

Remember though, the Rule of 72 is designed to be a rough estimate and its assumptions aren't always realistic. It assumes a constant rate of return, and stock returns are anything but constant. The ...