Archive · 19 Sep 2026
Rule of 72 Estimates How Quickly ₹1 Lakh Doubles
The Rule of 72 is a quick way to estimate how long money may take to double.
You divide 72 by the yearly return percentage.
If the return is 6%, ₹1 lakh may take about 12 years to become ₹2 lakh.
At 8%, it may take about 9 years.
At 10%, it may take about 7.2 years.
A higher return can make money grow faster.
However, real investments may not earn the same return every year.
Taxes, fees and inflation can reduce the final amount.
The rule is only an estimate, not a promise.
The Rule of 72 estimates doubling time by dividing 72 by the annual rate of return.
At 6%, ₹1 lakh could take approximately 12 years to become ₹2 lakh.
At 8%, the estimated doubling period is about 9 years.
At 10%, ₹1 lakh could double in approximately 7.2 years.
Taxes, fees, inflation, risks and changing returns can affect the actual outcome.
- Who
- Investors and people planning their personal finances.
- What
- The Rule of 72 is used to estimate how long an investment may take to double.
- When
- The calculation applies over an estimated investment period; no specific date is given.
- Where
- It can be used when comparing investment returns, including fixed-deposit rates offered by various lenders.
- Why
- To quickly compare rates of return and understand the effects of compounding on wealth growth.
- Formula
- Approximate doubling time = 72 ÷ annual rate of return.
- Starting investment
- ₹1 lakh.
- At 6%
- Approximately 12 years to reach ₹2 lakh.
- At 8%
- Approximately 9 years to reach ₹2 lakh.
- At 10%
- Approximately 7.2 years to reach ₹2 lakh.
- Illustrative 25% rate
- Approximately 2.88 years to double.
- Fixed-deposit range cited
- Approximately 6% to 8.5%, implying a doubling period of about 8.4 to 12 years.