Lumpsum vs SIP Calculator

In a steadily rising market, lumpsum always wins mathematically because the entire capital compounds from day one. A ₹12 lakh lumpsum at 12% for 10 years grows to about ₹37 lakh, while the same amount invested as ₹10,000 per month SIP grows to about ₹23 lakh. The SIP investor's average deployed capital is only ₹6 lakh for most of the period, not ₹12 lakh. However, in volatile or falling markets, SIP wins by accumulating more units at lower prices during corrections. Since no one can reliably predict market direction, SIP or STP is the safer default for most investors.

STP (Systematic Transfer Plan) is a facility where you park a lumpsum in a low-risk fund (overnight, liquid, or ultra-short duration fund earning 6-7%) and automatically transfer a fixed amount each month to an equity fund. Unlike a direct SIP where money sits idle in a bank account, STP puts the entire lumpsum to work immediately in the liquid fund while gradually building equity exposure. STP is ideal when you have a windfall (bonus, FD maturity, RSU vest) and are unsure about market timing. It gives the averaging benefit of SIP plus the idle cash benefit of liquid fund returns.

Lumpsum is clearly better in three situations: (1) during or immediately after a market correction of 20% or more - low NAVs amplify future gains and the downside has already been absorbed; (2) when you have a very long horizon of 15+ years, since market volatility smooths out over time and the lumpsum compounding advantage compounds further; (3) when the investment is in debt funds or fixed-income instruments with predictable, non-volatile returns. For equity in normal or elevated market conditions, STP over 6-12 months is usually the better risk-adjusted choice over pure lumpsum.

Yes, for salaried investors SIP is almost always the correct approach - and it is not even a close decision. Your income arrives monthly, so investing monthly is natural and aligned with your cash flow. SIP enforces the pay-yourself-first principle automatically: money leaves the account before you can spend it. It also removes market timing decisions entirely, which research shows most investors get wrong. The lumpsum vs SIP question only becomes relevant when a windfall arrives - an annual bonus, inheritance, insurance payout, or maturity proceeds. For regular monthly savings from salary, SIP is always the answer.

Rupee cost averaging means investing a fixed amount regularly automatically buys more units when prices are low and fewer when prices are high. For example, investing ₹10,000 per month: at NAV ₹100 you get 100 units; at NAV ₹80 (market dip) you get 125 units. Your average cost per unit becomes lower than the simple average NAV. This reduces the impact of buying at market peaks. Lumpsum investing at the wrong time - for instance, in January 2008 at Sensex 21,000 before it crashed to 8,000 - can take 5 years to break even. The same total amount via SIP from 2008 was profitable by 2010 because it kept buying through the crash at lower prices.

Yes, significantly. If a lumpsum is invested at a market peak and the subsequent years are poor, the SIP alternative will outperform because it accumulates more units during the downturn. If the lumpsum is invested at a market trough, it dramatically outperforms SIP because the entire capital compounds from the low point. Since no one reliably knows when the market is at a peak or trough, the expected outcome across random market timing favours SIP for most investors. Research on US and Indian market data shows that a lumpsum outperforms SIP in about 60 to 70% of historical 10-year windows - because markets rise more often than they fall. But the 30 to 40% of windows where lumpsum underperforms often involve severe downturns (2008, 2020) that can permanently derail an investor's financial plan. This asymmetric risk makes STP the rational default for large windfalls.

STP lets you deploy a lumpsum gradually from a low-risk fund into an equity fund, combining the benefits of immediate deployment with the averaging benefit of SIP. Step 1: Invest the full lumpsum into a liquid fund or overnight fund (earning 6 to 7% while sitting there). Step 2: Set up an STP instruction to automatically transfer a fixed amount each month to your target equity fund. Step 3: Watch the liquid fund balance decrease and the equity fund balance grow over 6 to 12 months. Unlike a direct SIP from a savings account (where the uninvested balance earns 2 to 4% in savings), STP earns 6 to 7% on the uninvested portion throughout the transfer period. For a Rs. 12 lakh lumpsum transferred over 12 months at Rs. 1 lakh per month, the liquid fund portion earns approximately Rs. 30,000 to Rs. 40,000 in additional returns compared to a direct SIP from a savings account.