The Rule of 72 is a quick mental shortcut to estimate how long an investment takes to double in value. Divide 72 by the annual rate of return to get the approximate number of years.
Years to Double ≈ 72 / Annual Return Rate (%)
At 8% annual return, your money doubles in approximately 72 / 8 = 9 years. At 12%, it doubles in 6 years. At 4%, it takes 18 years.
AllInvestView shows CAGR on your dashboard. Try our compound interest calculator for precise projections.
Very accurate for rates between 4-15%. At 8%, the rule predicts 9.0 years; the exact answer is 9.01 years. Accuracy decreases at very high or very low rates.
Yes — at 3% inflation, your money loses half its purchasing power in about 72/3 = 24 years. It works for any compounding rate.