Why this matters: A SIP (Systematic Investment Plan) is one of the simplest and most powerful ways to build wealth in India. It makes investing disciplined and affordable — you invest a fixed amount regularly, letting compounding and rupee-cost averaging work in your favour. A SIP calculator removes guesswork by showing exactly how your monthly contributions grow over time under different return assumptions.
What is SIP (Systematic Investment Plan)?
SIP lets you invest a fixed amount (monthly/quarterly) into a mutual fund. Each contribution buys units at the prevailing NAV — more units when NAV is low, fewer when NAV is high (rupee cost averaging). Over the long term, recurring investments combined with compounding can produce substantial wealth.
The SIP (Future Value) formula
For periodic investments made at the end of each period (ordinary annuity), the future value (maturity amount) of a SIP is calculated as:
FV = P × [ ( (1 + r)^n − 1 ) / r ]
Where:
- FV = Future value (maturity amount)
- P = Periodic SIP amount (e.g., monthly contribution)
- r = Periodic rate (for monthly SIP r = annual_rate / 12)
- n = Total number of periods (months = years × 12)
Worked example — step-by-step (digit-by-digit)
Scenario A: Monthly SIP P = ₹5,000; Expected annual return = 12% p.a.; Investment period = 10 years.
Step 1 — Convert annual rate to monthly periodic rate:
Annual rate = 12% → monthly rate r = 12% / 12 = 1% = 0.01
Step 2 — Number of periods:
Years = 10 → n = 10 × 12 = 120 months
Step 3 — Compute (1 + r)^n (raise 1.01 to the 120th power):
1 + r = 1.01 (1.01)^120 ≈ 3.3003868945736685
Step 4 — Compute numerator = (1 + r)^n − 1:
(1.01)^120 − 1 = 3.3003868945736685 − 1 = 2.3003868945736685
Step 5 — Divide numerator by r:
2.3003868945736685 ÷ 0.01 = 230.03868945736684
Step 6 — Multiply by P to get FV:
FV = 5,000 × 230.03868945736684 = ₹1,150,193.4472868342
Result: After 10 years of ₹5,000/month at 12% p.a., the SIP will grow to approximately ₹11,50,193.
Another example — longer horizon
Scenario B: Monthly SIP P = ₹2,000; Annual return = 10% p.a.; Period = 20 years (240 months).
Monthly r = 10% / 12 ≈ 0.008333333333333333 (1 + r)^240 ≈ 3.384685417 Numerator = (1+r)^240 − 1 ≈ 2.384685417 Divide by r: ≈ 2.384685417 / 0.008333333333333333 ≈ 286.1358889899614 FV = 2,000 × 286.1358889899614 ≈ ₹1,518,737.67
Result: ₹2,000 per month for 20 years at 10% p.a. ≈ ₹15.19 lakh.
Quick comparison table — same SIP, different return rates
Monthly SIP: ₹5,000; Period: 10 years (120 months). Results shown below:
| Annual Return (p.a.) | Monthly r | (1+r)^n | FV (approx.) |
|---|---|---|---|
| 10% | 0.10 / 12 = 0.0083333333 | ≈ 2.029 | ₹10,24,224.89 |
| 12% | 0.12 / 12 = 0.01 | ≈ 3.3003868946 | ₹11,50,193.45 |
| 14% | 0.14 / 12 ≈ 0.0116666667 | ≈ 4.090 | ₹12,95,344.56 |
How a SIP Calculator works (behind the scenes)
- Take your inputs: periodic contribution (P), expected annual return, frequency (monthly), and investment tenure (years).
- Convert annual return to periodic rate (monthly rate = annual / 12).
- Compute n = years × 12 (total periods).
- Apply the SIP future-value formula: FV = P × [((1 + r)^n − 1) / r].
- Display results, and optionally show an amortization-like table that lists cumulative contributions, estimated returns, and growth year-by-year.
- The formula assumes contributions at period end (ordinary annuity). If contributions are at period start, multiply result by (1 + r).
- Returns used are nominal expectations. Real returns = nominal − inflation.
- Actual mutual fund returns vary — use conservative estimates and run multiple scenarios in the calculator.
Why SIPs are powerful
- Compounding: Earnings generate further earnings — the longer you stay invested, the larger the compounding effect.
- Rupee Cost Averaging: Investing the same amount regularly reduces the effect of volatility on purchase price.
- Discipline: SIPs automate investing and remove timing risk.
Try our SIP Calculator
Quickly test different monthly amounts, durations and return assumptions with our interactive SIP Calculator:
Frequently asked questions
Q: Is SIP better than lump-sum?
A: SIP is better when you prefer disciplined investing and want to average out market volatility. Lump-sum can outperform if invested at a market low and returns are high. Use both strategically.
Q: What should I assume as expected return?
A: For equity SIPs, long-term historical equity returns in India have ranged 10%–15% depending on fund and period. Use conservative assumptions (8%–12%) for planning.
Q: Does the SIP calculator predict exact returns?
A: No — a SIP calculator uses assumed constant returns to project growth. Real returns fluctuate; use the calculator for scenario planning, not guaranteed outcomes.
Disclaimer: Illustrations are for educational purposes. Past performance is not indicative of future returns. Consider consulting a certified financial planner for personalised advice.