Rule of 72

The Rule of 72 is a quick way to estimate how long it takes for an investment to double in value given a fixed annual interest rate. You simply divide 72 by the interest rate percentage. For example, at an 8% rate, it takes about 9 years (72 ÷ 8) to double your money. It’s a handy shortcut for understanding the impact of compound interest and comparing investment growth. Keep in mind, it’s an approximation that works best with interest rates between 6% and 10%.