The 15-15-15 Rule vs. Reality: Tracking your way to 1 Crore

The 15-15-15 rule is an investment idea widely used in goal-based financial planning. Under this rule, you invest ₹15,000 every month through a SIP for 15 years. The investment is assumed to earn an average return of 15% per year.

Now, over 15 years, your total contribution is ₹27 lakhs (₹15,000 × 12 months × 15 years). This is the actual money you put in. Next, the growth happens because of “compounding”. Each monthly investment earns returns. Gradually, those returns stay invested and also earn returns. 

As the investment period increases, the total value grows faster because both the invested amount + past gains grow together. Let’s see what may happen if the mutual fund delivers an average return close to 15% over the full 15 years: 

So, exactly, the value of your ₹27 lakh investment becomes ₹92,45,484 (which is still ₹7,54,516 less than ₹1 crore) by the end of the period. Okay, so is this rule a guarantee? Nope! 

Realise that mutual fund returns depend on market conditions and can vary each year. In personal financial planning, this rule only shows the importance of:

• Regular investing

• Long investment duration

• The impact of compounding

Next, let’s understand why its assumptions might not hold in 2026 and beyond. 

When it comes to personal finance management, several advisors blatantly promote the 15-15-15 rule. Realise that the rule is just a “simplified illustration” and not a reflection of how investing works in real life. 

It is designed only to explain the concept of long-term investing + compounding. This financial planning rule ignores many factors that influence actual returns. Let’s check them out:  
 

1. Mutual Fund Returns are Always Variable

The 15-15-15 rule assumes that a mutual fund will give a 15% return every year for 15 years. This does not happen in real markets. To understand better, let’s analyse the data provided by the NSE archives.

• Nifty 50 Annualised Returns are 13.32%

  Since June 30, 1999 (till December 2025), the Nifty 50 Total Return (TR) index has given annualized returns of 13.32% CAGR with annualised volatility of 21.76%. (Source: Till the latest data available from NSE). Even India's top 50 companies have delivered an average return of 13.32%. This is 1.68% lower than the 15% return assumed under the 15-15-15 rule. 

  Is this a minor difference? Nope! Over a 15-year investment period, it can lead to a significant shortfall in the final corpus. If we calculate, a 13.32% average return reduces your corpus to ₹79,95,006 (a deficit of ₹6,19,468 from ₹12,50,478 and ₹20,04,994 from ₹1,00,00,000). 

   

2. Investment Costs + Taxes Reduce Final Returns

The 15-15-15 rule shows a “gross return” of ₹92,45,484. It ignores the costs involved in mutual fund investing. Let’s check them out:

Since the 15-15-15 rule does not subtract these costs, the final corpus shown under higher than what most investors may actually receive.

3. Inflation Reduces the Real Value of the Final Corpus

The 15-15-15 rule of financial investment planning ignores inflation. Even if an investor manages to accumulate approximately ₹1 crore after 15 years, that amount will not have the same value as ₹1 crore today. But why? That’s because inflation decreases “purchasing power” and directly reduces the worth of your future value. 

Need clarity? Let’s calculate the actual worth of ₹1 crore after 15 years at 7% inflation (assumed) using the following formula:

Real Value = Future Amount / (1 + Inflation Rate)ⁿ

Where:

• Future Amount = ₹1,00,00,000

• Inflation Rate = 7% or 0.07

• Time Period = 15 years

Real Value = ₹1,00,00,000 / (1 + 0.07)¹⁵

Real Value = ₹1,00,00,000 / 2.76

Real Value = ₹36,20,000

Now, if inflation averages 7% per year, then ₹1 crore received after 15 years will have the purchasing power of only about ₹36 lakh today. Thus, the 15-15-15 rule only shows “nominal wealth creation” and does not reflect real wealth after accounting for inflation.

So now you know about an important concept of Finance 101, the 15-15-15 rule. In 2026, it is useful only as a “teaching concept” because it shows the power of compounding and the value of long-term + disciplined investing through SIPs. 

It should not be treated as a guarantee because accumulating ₹1 crore by investing ₹15,000 per month for 15 years depends on several assumptions that may rarely hold true.

In reality, mutual fund returns are not fixed and may fall short of 15% over long periods. The final corpus could be further reduced by capital gains tax and ongoing fund expenses, such as the expense ratio. Moreover, the rule also ignores inflation and timing risk.