The 15-15-15 Rule: How a ₹15,000 SIP Can Build Your First Crore
₹15,000 a month, a 15% expected return, for 15 years. The 15-15-15 rule promises a crore at the end of it — here's whether the math actually holds up.
The 15-15-15 rule is one of those pieces of finance advice that sounds too clean to be real: invest ₹15,000 a month, assume a 15% annual return, stay in for 15 years, and you end up a crorepati. Three matching 15s, one crore rupees. It’s the kind of thing that circulates on social media precisely because it’s catchy, which is usually a good reason to be suspicious of it. So let’s actually run the number.
Does the math check out?
Using the same compounding formula behind our own SIP Calculator — monthly investments compounding at the start of each period, the standard convention for SIPs — a ₹15,000 monthly SIP at a 15% assumed annual return, continued for exactly 15 years, works out to:
- Total invested: ₹27,00,000
- Future value: ₹1,01,52,946
- Wealth gained purely from growth: ₹74,52,946
So yes, the rule holds. Not approximately, not “close enough with rounding” — the actual number comes out slightly past a crore, at roughly ₹1.015 crore. Out of that final amount, you put in ₹27 lakh yourself; the market did the other ₹74.5 lakh, which is nearly three times what you actually contributed.
💡 Aha moment
You contributed ₹27 lakh in total. Growth alone added another ₹74.5 lakh on top of that — more than double what you actually paid in. That's not a rounding error or a lucky assumption; it's what 15 years of compounding at 15% genuinely does to a monthly SIP. The three 15s aren't a coincidence of good marketing, they're a real combination that happens to land almost exactly on a round number.
Why all three 15s matter, not just one of them
The rule works because of how the three inputs interact, and changing any single one breaks it more than you’d expect.
Drop the return to 12% (a more conservative, arguably more realistic long-term equity assumption) and the same ₹15,000 for the same 15 years lands at roughly ₹75.7 lakh — a full 25 lakh short of a crore. The extra 3 percentage points of assumed return isn’t a rounding detail; it’s the difference between hitting the target and missing it by a quarter.
Drop the tenure to 10 years instead of 15, keeping the 15% return, and the SIP only reaches about ₹41.8 lakh — less than half the target, despite two-thirds of the monthly contributions. This is compounding’s most counterintuitive property: the last five years of a long SIP typically add more to the final value than the first ten combined, because by then a much larger base is earning returns.
Push the same SIP to 20 years instead of 15, and it grows to roughly ₹2.27 crore — more than double the 15-year figure, off just five extra years of the same monthly contribution. That’s the same compounding effect working in your favour if you can afford to stay invested longer than the rule asks for.
The part the catchy version leaves out
A 15% return is an assumption, not a promise, and it’s worth being honest about where that number comes from: it’s roughly in line with what some equity mutual fund categories have delivered over long historical periods in India, not a guaranteed or risk-free rate the way a bank FD’s rate is. Markets don’t compound smoothly in real life the way this formula assumes — some years will return 25%, others will lose money, and the eventual average is what the formula is really approximating. A SIP that runs the full 15 years without interruption tends to smooth out a lot of that volatility, which is part of why the “stay invested” instruction matters as much as the “15%” one.
It’s also worth being clear that nothing here is specific to any one mutual fund or investment product. The 15-15-15 rule is a mental-math shortcut for what steady, long-term SIP investing at an assumed rate can do, not a recommendation to invest in any particular fund.
Running it for your own numbers
The 15-15-15 rule is a memorable starting point, not a target you’re locked into. If ₹15,000 a month isn’t realistic for you right now, or if you’d rather plan around a different return assumption or a different time horizon, use the SIP Calculator to see what your own combination actually adds up to — and if you know your target and want to work backward to the required monthly amount, the Goal SIP Calculator does exactly that.
Learn more from official sources
- AMFI Investor Education — how SIPs work and general mutual fund investing guidance.
- SEBI Investor Education — risk disclosures and investor protection for market-linked investments.
This is general information, not investment advice. Mutual fund returns are market-linked and not guaranteed — a 15% return is an assumption for illustration, not a promise of future performance. Consult a qualified financial advisor before making investment decisions.