Lumpsum vs SIP: Which Is Better? The Honest Maths

If you already have the money and will stay invested for 10 years or more, a lumpsum has the edge in plain maths: every rupee goes to work from day one. ₹6 lakh invested at once at a steady 12% grows to about ₹18.64 lakh in 10 years, while ₹5,000 a month (the same ₹6 lakh in total) grows to about ₹11.62 lakh. But that comparison only matters if you actually have ₹6 lakh today, and it ignores the risk of the market falling right after you invest.

This guide works through the numbers step by step, shows rupee-cost averaging with a small price series you can check by hand, and ends with a simple decision table. You can repeat every figure with the lumpsum calculator and the SIP calculator. The 12% return is an illustration, not a forecast: equity fund returns are not guaranteed and vary a lot from year to year.

The headline comparison: ₹6 lakh at once vs ₹5,000 a month

Take two investors with the same ₹6 lakh. Asha invests all of it today. Ravi invests ₹5,000 at the start of every month for 10 years (120 instalments, also ₹6 lakh). Both earn the same illustrative 12% a year.

After 10 years at 12%	Lumpsum (Asha)	SIP (Ravi)
Money put in	₹6,00,000	₹6,00,000
Value after 10 years	₹18,63,509	₹11,61,695
Gain	₹12,63,509	₹5,61,695
Growth multiple	3.11×	1.94×

Here is the working, so you can see where each number comes from.

• Lumpsum: ₹6,00,000 × 1.12¹⁰ (1.12 multiplied by itself 10 times) = ₹6,00,000 × 3.1058 = ₹18,63,509. After year 1 it is ₹6,72,000, after year 5 ₹10,57,405, and it roughly doubles every six years.
• SIP: the SIP calculator treats 12% a year as 1% a month and assumes each instalment goes in at the start of the month. Value = ₹5,000 × [(1.01¹²⁰ − 1) ÷ 0.01] × 1.01 = ₹5,000 × 232.34 = ₹11,61,695.

One technical point works in the SIP's favour: 1% a month compounded is slightly more than 12% a year (about 12.68%), while the lumpsum calculator compounds once a year at exactly 12%. So the table, if anything, flatters the SIP, and the lumpsum still ends about ₹7 lakh ahead.

Why the lumpsum wins when returns are steady

It comes down to how long each rupee is invested. Asha's whole ₹6 lakh is invested for 120 months. Ravi's first ₹5,000 is invested for 120 months, but his last ₹5,000 for only one month. On average his money is in the market for (120 + 1) ÷ 2 = 60.5 months, about five years. Half the time in the market means far less compounding, and nothing about SIP can make up for that if the market simply rises steadily.

Inflation trims both results. At 6% inflation, Asha's ₹18.64 lakh would buy about as much as ₹10,40,574 does now (the lumpsum calculator shows this line when you fill in the inflation box). The SIP's ₹11.62 lakh shrinks by the same proportion. The inflation calculator shows the same effect on any amount.

Why the comparison is unfair if you don't have ₹6 lakh today

Most salaried people never face the choice in the table. Your money arrives as a monthly salary, so the real alternatives are "invest ₹5,000 every month" or "save ₹5,000 a month in a bank account until you have ₹6 lakh, then invest it". The second plan takes 10 years to collect the lump sum, so it is plainly worse.

Seen this way, a SIP is not the opposite of a lumpsum. It applies the same rule that made Asha win: invest money as soon as you have it. Asha invested on the day she had ₹6 lakh. Ravi invests on the day each ₹5,000 arrives. The lumpsum vs SIP question only becomes real when a large amount lands at once: an annual bonus, a matured FD or PPF account, an inheritance or the proceeds of a property sale.

Rupee-cost averaging, worked out by hand

A SIP buys more units when the price (the NAV) is low and fewer when it is high. Here are two made-up four-month price series, each with ₹5,000 a month (₹20,000 in total), compared with putting the whole ₹20,000 in during month 1.

Month	Dip then recovery: NAV	Units for ₹5,000	Steady rise: NAV	Units for ₹5,000
1	₹100	50	₹50	100
2	₹80	62.5	₹62.50	80
3	₹50	100	₹80	62.5
4	₹80	62.5	₹100	50
Total		275 units		292.5 units

Dip then recovery. Units bought = 5,000 ÷ 100 + 5,000 ÷ 80 + 5,000 ÷ 50 + 5,000 ÷ 80 = 50 + 62.5 + 100 + 62.5 = 275. Your average cost is ₹20,000 ÷ 275 = ₹72.73 a unit, below the simple average of the four prices (₹77.50). At the month-4 NAV of ₹80, the SIP is worth 275 × ₹80 = ₹22,000, a gain of ₹2,000, even though the price is still 20% below where it started. The lumpsum bought 200 units at ₹100 and is worth 200 × ₹80 = ₹16,000, a loss of ₹4,000.

Steady rise. Units bought = 100 + 80 + 62.5 + 50 = 292.5, average cost ₹20,000 ÷ 292.5 = ₹68.38. At ₹100 the SIP is worth ₹29,250. The lumpsum bought 400 units at ₹50 and is worth ₹40,000. Here the lumpsum wins clearly.

Two lessons follow. First, a SIP's average cost is always at or below the simple average of the prices you bought at, because fixed rupee amounts automatically buy more units at low prices. Second, that does not make a SIP better than a lumpsum. Rupee-cost averaging helps only in the paths where prices dip during your buying period. If you expect markets to rise over your horizon (which is the reason to buy equity funds at all), investing earlier is the better bet on average.

What if the market falls right after you invest a lumpsum?

This is the real fear, so here is a hypothetical. Asha invests ₹6 lakh and the market falls 30% in the first year. Her investment is now worth ₹6,00,000 × 0.70 = ₹4,20,000. To get back to ₹6 lakh it must rise 6,00,000 ÷ 4,20,000 − 1 = 42.9%, not 30%, because the recovery starts from a smaller base.

Suppose the market then earns a steady 12% a year for the remaining nine years. The lumpsum calculator gives:

• ₹5,90,070 after three more years and ₹6,60,878 after four, so it takes about four years just to get back above ₹6 lakh.
• ₹11,64,693 at the end of year 10, against ₹18,63,509 in the smooth scenario. One bad first year cost ₹6,98,816 of final value.

Ravi, the SIP investor, had at most ₹60,000 in the market by the end of that first year, so a 30% fall could cost him no more than ₹18,000 on paper, and his remaining 108 instalments would buy at the lower prices. His result would be dented too, but far less than Asha's.

Notice something else: even after the crash, Asha's ₹11.65 lakh is about what Ravi earned in the smooth scenario (₹11.62 lakh). A lumpsum does not have to be timed perfectly to do well. The bigger danger is behavioural. An investor who panics and sells after the 30% fall locks in the ₹1.8 lakh loss and misses the recovery. If you know you would do that, the SIP or STP route is worth its cost.

STP: the middle path for a lump sum

A systematic transfer plan (STP) splits the difference. You put the lump sum into a liquid or short-term debt fund and instruct the fund house to move a fixed amount at regular intervals (daily, weekly or monthly) into an equity fund of the same fund house. Your money earns something while it waits, and it enters equity in steps.

Worked example, again at a steady 12% for illustration: ₹6 lakh moved in 12 monthly transfers of ₹50,000.

1. The equity side behaves like a one-year SIP of ₹50,000 a month. The SIP calculator gives ₹6,40,466 after 12 months.
2. That amount then grows for the remaining nine years. The lumpsum calculator gives ₹17,76,063.
3. The straight lumpsum gave ₹18,63,509, so in a steady market the STP costs about ₹87,446 over 10 years, partly offset by the interest the waiting money earns in the liquid fund (left out here).

In return, a crash in the first year would hit only the part already transferred. A short STP (6 to 12 months) keeps most of the lumpsum's time advantage. Spreading a lump sum over three or more years gives most of it away and starts to look like Ravi's SIP.

Two costs to check before you set one up. Each transfer is a redemption from the source fund, so the small gain on those units is taxed; for debt funds bought on or after 1 April 2023, gains are taxed at your slab rate whatever the holding period. And some funds charge an exit load on redemptions within a set period, which the scheme documents state.

Decision table: lumpsum, SIP or STP?

Your situation	Better fit	Why
Monthly salary, no lump sum	SIP	Invests each rupee as soon as it arrives
Lump sum, 10+ year horizon, you can sit through a 30% fall	Lumpsum (or a short STP)	More time invested; higher expected value
Lump sum, 7+ years, a fall would make you sell	STP over 6–12 months	Limits the damage from bad timing
Money needed within about 3 years	Neither in equity	Use FD, RD or a debt fund instead
Annual bonus plus monthly salary	Both	Lumpsum or STP the bonus, SIP the salary
"The market looks too high"	STP, not waiting in cash	Waiting for a dip can take years

The horizon matters more than the method. For money needed in two or three years, compare safer options in RD vs FD vs SIP for ₹5,000 a month, or test a fixed deposit with the FD calculator.

Tax: how lumpsum and SIP units are treated

As of October 2026, gains on equity mutual fund units held for more than 12 months are taxed at 12.5% on total long-term gains above ₹1.25 lakh a year; units held 12 months or less are taxed at 20%, plus 4% cess in both cases. A lumpsum has one purchase date, so all its units turn long-term together after a year.

A SIP is different: every instalment is a separate purchase with its own 12-month clock, and units are redeemed first-in-first-out. If you redeem a SIP that is 18 months old, the oldest 12 months of units count as long-term and the newest six months as short-term. Plan redemptions with that in mind.

What matters more than lumpsum vs SIP

• Staying invested. The gap between the best and worst entry timing is usually smaller than the damage from selling in a panic.
• An emergency fund first. Money you might need next month should not be in equity, however you invest it.
• Costs and fund choice. A lower expense ratio compounds in your favour every year.
• The exit plan. When you later need regular income from the corpus, a systematic withdrawal plan reverses the SIP. See how long an SWP lasts.

For the basics of how monthly investing grows, SIP calculator: how much will your investment grow? covers the formula in more detail.

This article is general information, not investment or tax advice; returns shown are illustrative and real returns will differ.

Frequently asked questions

Is lumpsum better than SIP for the long term?

On average, yes, if you already have the money, because it is invested for longer. Over 10 years at a steady 12%, ₹6 lakh invested at once grows to ₹18.64 lakh, against ₹11.62 lakh for ₹5,000 a month. The lumpsum carries more timing risk, so it suits people who will not sell during a fall.

Can I invest a lumpsum and run a SIP in the same fund?

Yes. Mutual funds generally accept additional purchases in the same folio, so you can add a bonus as a lumpsum while your monthly SIP continues. Each purchase has its own date for tax purposes.

When is the best time to invest a lump sum?

Nobody can identify it reliably in advance. If you are worried about a fall, an STP over 6 to 12 months is a practical compromise; waiting in cash for a dip that may not come costs returns too.

Does SIP give better returns in a falling market?

A SIP running through a fall buys more units at lower prices, so it recovers faster than a lumpsum made at the top. In the four-month example above, the SIP showed a ₹2,000 gain while the lumpsum showed a ₹4,000 loss at the same price.

Is the 12% return in these examples guaranteed?

No. It is a round number used to compare methods fairly. Equity fund returns change every year and can be negative for several years in a row.

Sources: EthicalFusion lumpsum and SIP calculators (12% illustrative return, figures as shown by the tools); Income-tax Act, 2025 and Finance Act, 2026 capital gains rates for mutual funds (as of October 2026); fund house descriptions of systematic transfer plans (HDFC Mutual Fund investor education).