⏳ Rule of 72 Calculator
The Rule of 72 is a quick mental-math shortcut: divide 72 by the annual rate of return to estimate how many years it takes an investment to double. It's an approximation, not an exact formula — useful for back-of-envelope thinking.
Years to double
Tip: 12% is a common long-term assumption for Indian equity mutual funds; adjust for your own expectation.
Result
Time to double your money
6.0 years
at 12% per year (72 ÷ 12 = 6)
Doubles again in
12.0 yrs
4x (two doublings) in
12.0 yrs
Reverse: rate needed to double in N years
14.4%
Note: The Rule of 72 is most accurate for rates between roughly 6% and 20%. For very high or very low rates, use the exact compound interest formula (t = ln(2) / ln(1+r)) for precision.
Rule72 tools are for educational purposes only and do not constitute financial advice. Actual investment returns are never guaranteed and vary over time.