How lumpsum compounding works
A lumpsum investment is a single one-time deposit into a mutual fund. Unlike a SIP where you invest regularly, the full principal is deployed immediately — meaning the entire amount starts compounding from day one.
The future value formula is: FV = P × (1 + r)^n
Where P is your principal, r is the annual return rate, and n is the number of years. The exponential nature of this formula means small differences in return rate or tenure produce large differences in maturity value over long periods.
Example: ₹1 lakh at 12% annual return:
- 10 years → ~₹3.10 lakh (3.1× your money)
- 20 years → ~₹9.65 lakh (9.6× your money)
- 30 years → ~₹29.96 lakh (30× your money)
This doubling-and-redoubling effect — compounding — is why starting early matters far more than the exact return rate.
When lumpsum vs SIP makes sense
| Scenario | Lumpsum | SIP |
|---|---|---|
| Received a windfall (bonus, inheritance) | Better — deploy all at once | Sub-optimal — leaves cash idle |
| Market at a cyclical low | Better — buys more units | Neutral — averages over future |
| Market at an all-time high | Risky — full exposure at peak | Better — averages entry cost |
| Regular monthly savings | Not applicable | Natural fit |
| Retirement corpus already built | Deploy via SWP | Not applicable |
Neither approach is universally superior. If you have a lumpsum during market uncertainty, a SIP-like staggered deployment (STP — Systematic Transfer Plan) from a liquid fund can also reduce timing risk.
What return rate is reasonable?
| Fund type | Historical 10-yr CAGR | Conservative assumption |
|---|---|---|
| Large-cap equity | 11–13% | 10–12% |
| Mid/small-cap equity | 13–17% | 12–14% |
| Hybrid (balanced) | 9–11% | 8–10% |
| Debt | 6–8% | 6–7% |
| ELSS (tax-saver) | 11–14% | 10–12% |
These are educational ranges based on historical data. Past performance is not indicative of future returns. BachatCalculator does not recommend specific funds.
Tax treatment
- ELSS lumpsum qualifies for §80C deduction up to ₹1.5L per FY (mandatory 3-year lock-in per investment tranche).
- Equity MF redemptions after 1 year: LTCG at 12.5% (post-23-Jul-2024) on gains above ₹1L per FY.
- Equity MF redemptions within 1 year: STCG at 20% (post-23-Jul-2024).
- Debt MF (purchased post 1-Apr-2023): gains taxed at slab rate regardless of holding period (Finance Act 2023). See our debt MF capital gains calculator.
Use the LTCG equity calculator to compute the exact after-tax return on your lumpsum redemption.
Where to invest your lumpsum
Bridges
- SIP calculator — compare systematic vs one-time investment
- Step-up SIP calculator — project increasing periodic contributions
- SWP calculator — plan systematic withdrawals from a lumpsum corpus
- LTCG equity calculator — tax on equity MF redemption gains
- Section 80C calculator — quantify ELSS lumpsum tax deduction