Discover exactly how long it takes to double your money.
The Rule of 72 is a famous mathematical shortcut used in finance to quickly estimate the number of years required to double your invested money at a given annual rate of return.
You simply divide the number 72 by your expected annual interest rate.
Example: If you expect an 8% return from the stock market, you calculate 72 / 8 = 9. It will take approximately 9 years for your portfolio to double in size.
Understanding this rule completely changes how you view long-term investing. It visually demonstrates the power of compound interest. If you invest $50,000 at age 30 and earn a 10% return (doubling every 7.2 years), that money will double nearly five times before you retire at 65, turning into over $1.5 Million—without you adding another dime.