Instantly find how long it takes to double your money at any CAGR, or what return you need to double in a target timeframe. Includes a comparison across savings, FD, PPF, and equity.
Instantly find how long it takes to double your money at any CAGR, or what return you need to double in a target timeframe. Includes a comparison across savings, FD, PPF, and equity.
At 12% annual return, your money doubles in
6.0
years
Exact calculation: 6.12 years (Rule of 72 is a close approximation)
Formula: 72 ÷ 12 = 6.0 years
Doubling Time Comparison
| Investment | Rate | Years to Double | Doubles in 20 yrs |
|---|---|---|---|
| Savings account (3.5%) | 3.5% | 20.6 yrs | 1× (0 doublings) |
| FD - SBI 5yr (7.0%) | 7% | 10.3 yrs | 2× (1 doublings) |
| PPF (7.1%) | 7.1% | 10.1 yrs | 2× (1 doublings) |
| Nifty avg CAGR (12%) | 12% | 6.0 yrs | 8× (3 doublings) |
| Midcap avg CAGR (15%) | 15% | 4.8 yrs | 16× (4 doublings) |
| Small cap avg (18%) | 18% | 4.0 yrs | 32× (5 doublings) |
| Inflation (6%) | 6% | 12.0 yrs | 2× (1 doublings) |
| Your Rate (12%) | 12% | 6.0 yrs | 8× (3 doublings) |
DETAILS
This section explains what the calculator does, what goes into the result, and how to interpret the output so you can apply it confidently.
This calculator turns a few key inputs into a clear output you can act on — a number that traders and investors commonly use for planning and decision-making.
Use it to compare scenarios quickly and to understand the trade-offs behind the final result.
Treat the output as a planning number. Small changes in inputs (time, rate, price, quantity, risk, or cashflows) can change the outcome meaningfully — so keep assumptions realistic.
If the tool returns multiple outputs, focus on the ones that drive decisions (e.g., net result, breakeven, or risk-adjusted value), not just the biggest number.
Rate 12% p.a.
Graphical view
Want to double in 9 years
Graphical view
HOW IT WORKS
Know the rate? Find doubling years. Know the timeframe? Find required rate.
Input your annual return rate % or target number of years to double.
Get your answer and a comparison table across savings, FD, PPF, and equity investments.
FAQ
Divide 72 by the annual return rate to find how many years it takes to double your money. At 12% CAGR: 72 ÷ 12 = 6 years. At 6% (inflation): 72 ÷ 6 = 12 years — meaning your money's purchasing power halves in 12 years at 6% inflation.
It is a very close approximation. The exact formula uses natural logarithm: Years = ln(2) / ln(1 + rate). Rule of 72 is accurate within ±1% for rates between 6–20%. For very low (0–2%) or very high (25%+) rates, accuracy reduces.
69.3 (= 100 × ln(2)) is the mathematically exact constant. Rule of 69 works for continuous compounding. Rule of 72 is preferred because 72 has more divisors (2,3,4,6,8,9,12) making mental math easier.
Use the inflation rate in the Rule of 72 to find how fast purchasing power halves. At 6% inflation: 72 ÷ 6 = 12 years. Your ₹10 lakh will have the buying power of ₹5 lakh in just 12 years if not invested.
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