Rule of 72 Favors the Prepared Mind
Are you familiar with the Rule of 72? It’s a shorthand way of calculating how long it will take for your money to double. Take an interest rate—say, 7 percent. Divide 7 into 72, and that’s a little over 10. That means it will take a little over 10 years for your money to double at a 7 percent rate of interest.