A breakdown of Lumpsum vs SIP and the trade-offs each strategy implies.
1. The Same Total Budget, Two Timing Strategies
You decide a total amount to invest — say ₹12 lakh over 10 years. The choice: deploy it all in one shot today (Lumpsum), or spread it evenly month by month (SIP). Both strategies put the same total rupees in, but the timing differs profoundly. Lumpsum money is exposed to compounding from day 1; SIP money trickles in over time, so each rupee gets less time to grow.
2. The Two Formulas
Lumpsum: FV = P × (1+r)n. Annual compounding on the entire principal for the full duration.
SIP: FV = SIP × [((1+rm)12n − 1) / rm] × (1+rm) where rm = (1+r)1/12 − 1. This is the annuity-due formula with the effective monthly rate. We use the effective rate (not the simple r/12) because it correctly accounts for compounding — this matches what platforms like Groww and Coin display.
3. Why Lumpsum Wins on Paper
At a constant, positive rate of return, Lumpsum will always beat SIP for the same total investment. Why? Because all your money has been growing since month 1. With a SIP, your final installment in month 120 has had zero time to compound — it just sits there at face value.
4. So Why Do Real Investors Choose SIPs?
Three reasons SIPs dominate in practice, despite losing this theoretical comparison:
(a) Rupee-cost averaging. Real markets aren't constant-rate — they go up and down. SIPs buy more units when prices are low, fewer when high, which can produce better returns than a single mistimed lumpsum during volatile periods.
(b) Behavioural discipline. SIPs automate investing. They remove the timing question (“is this a good time to invest?”) and force consistency.
(c) Capital availability. Most people don't have ₹12L sitting in a bank account. SIPs let you invest from monthly income.
This calculator assumes a constant rate (best-case for Lumpsum). In a real market with volatility, the gap typically shrinks significantly — and SIPs sometimes win.
5. Tax & Real Value
Both paths apply a flat 12.5% LTCG rate on gains. The Real Value column shows the future amount in today's purchasing power (FV ÷ (1+inflation)n).
Caveats & Disclaimer
Returns are illustrative. Mutual fund investments are subject to market risk; past performance does not guarantee future results. The constant-rate model is a simplification — in reality, returns vary year to year. The 12.5% LTCG assumption applies to equity/equity-oriented holdings held longer than 1 year. SIP tax in reality is calculated per installment based on holding period. Consult a financial advisor for personalised guidance.