A Systematic Investment Plan (SIP) lets you invest a fixed amount into a mutual fund every month instead of putting in a lump sum. It is one of the most popular ways to build long-term wealth in India because it combines two powerful forces: rupee-cost averaging and compounding. But most people never calculate what their SIP is actually likely to grow into — they just invest and hope.
How SIP Compounding Works
Every monthly SIP installment earns returns, and those returns are reinvested to earn further returns. Over a short period this looks unremarkable, but over 10-20 years the effect is dramatic — this is the same "compound interest" idea Einstein reportedly called the eighth wonder of the world. The earlier you start, the more months your money has to compound, which matters more than the actual amount you invest each month.
The SIP Future Value Formula
The maturity value of a SIP is calculated using:
M = P × [(1 + i)n − 1] / i × (1 + i)
Where:
- M = Maturity amount
- P = Monthly SIP installment
- i = Expected monthly return rate (annual rate ÷ 12)
- n = Total number of installments
A Real Example
Suppose you invest ₹5,000 every month for 15 years, expecting a 12% annual return (a commonly used long-term equity mutual fund assumption).
- Total amount invested over 15 years = ₹5,000 × 180 months = ₹9,00,000
- Estimated maturity value ≈ ₹25,22,880
- Wealth gained from returns alone ≈ ₹16,22,880
Nearly 64% of the final corpus in this example comes purely from compounding returns, not your own contributions — this is the core reason financial planners emphasize starting SIPs early rather than waiting to invest a larger amount later.
Why the Assumed Return Rate Matters
SIP calculators require you to enter an expected annual return rate, and this single number has the biggest impact on your projected corpus. Equity mutual funds have historically returned anywhere from 10-15% annually over long periods, but returns are never guaranteed and can vary year to year. It is safer to calculate your goal using a conservative estimate (10-12%) rather than an optimistic one, so you are not caught short if actual returns are lower.
Step-Up SIP: Increasing Your Investment Over Time
As your income grows, increasing your monthly SIP amount by even 10% every year (a "step-up SIP") can significantly boost your final corpus without feeling like a big jump in any single year. Our SIP calculator lets you experiment with different monthly amounts to see how small increases compound into large differences over a decade or more.
Calculate Your SIP Instantly
Instead of doing this math by hand, use our free SIP Calculator — enter your monthly investment, expected return rate and investment duration, and it instantly shows your estimated maturity value and total gains.
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