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The 15-15-15 Rule in Mutual Funds: How to Build a ₹1 Crore Corpus

By Sunil Srivastava • Published: August 2026 • 8 min read

Learn how the celebrated 15-15-15 mutual fund formula works, the mathematical proof behind ₹1 Crore compounding, and how you can apply Step-Up strategies to reach your goal even faster.

Key Takeaways

  • The 15-15-15 rule states: ₹15,000 monthly SIP × 15 Years duration × 15% assumed CAGR = ₹1.00 Crore wealth corpus.
  • Out of the ₹1.00 Crore total, your actual capital invested is only ₹27 Lakhs — the remaining ₹73 Lakhs is generated purely by compound interest.
  • Extending the timeline by just another 15 years (total 30 years) expands the corpus from ₹1.00 Crore to over ₹10.38 Crores due to the hockey-stick curve of compounding.
  • Adding a 10% annual Step-Up SIP reduces the time needed to reach ₹1 Crore from 15 years to just 11.5 years.

Demystifying the 15-15-15 Rule

The 15-15-15 rule is one of the most powerful and intuitive mental models in modern retail investing. It demonstrates how regular, disciplined investing can transform middle-class household savings into generational wealth without requiring a lump sum windfall.

The three 15s represent three specific levers: (1) ₹15,000 monthly investment, (2) 15 years of uninterrupted compounding, and (3) 15% annualized long-term equity growth.

The Mathematical Breakdown of ₹1 Crore

Let us inspect the numbers:

• Monthly Contribution: ₹15,000

• Investment Duration: 15 Years (180 months)

• Total Amount Deposited by You: ₹27,00,000

• Estimated Compounding Returns: ₹73,24,000

• Total Final Wealth Corpus: ₹1,00,24,000 (~₹1 Crore)

TIP: Notice that nearly 73% of your final wealth consists of compound gains, not your out-of-pocket savings. Time in the market is the greatest wealth multiplier.

The 15-15-30 Phenomenon: Turning ₹1 Crore into ₹10 Crores

If you do not withdraw your ₹1 Crore corpus after 15 years and simply continue investing ₹15,000/month for another 15 years (total 30 years):

• Total Invested across 30 years: ₹54 Lakhs

• Total Wealth Accumulated: ₹10.38 Crores!

This dramatic non-linear surge occurs because in the second 15 years, interest is earning interest on a multi-crore base.

Frequently Asked Questions

Is a 15% return guaranteed in mutual funds?

No. Mutual funds are market-linked instruments and do not offer guaranteed returns. Historical data of broad Indian equity indices (Nifty 50, Nifty 500) shows long-term 12-15% CAGR across 15-20 year rolling periods, but annual returns will fluctuate year to year.

What if I can only invest ₹5,000 or ₹10,000 per month?

The same compounding principles apply proportionately. A ₹5,000/month SIP for 15 years at 15% yields ~₹33.4 Lakhs, and ₹10,000/month yields ~₹66.8 Lakhs. Using an annual 10% Step-Up allows you to reach ₹1 Crore easily over time.

About Sunil Srivastava

AMFI-Registered Financial Distributor • VestiFi

Dedicated to helping families across India make transparent, goal-aligned decisions across mutual funds and risk protection.