Does rupee cost averaging guarantee a better price?

It guarantees an average cost below the average price over the period, which is not the same thing. If the market only rose, your average cost is still above the price on day one, so you bought at a worse effective price than investing immediately.

How many months should I spread a lumpsum over?

Six to twelve is the usual range. Beyond about eighteen months the return forgone on undeployed cash tends to outweigh any averaging benefit, and the plan becomes harder to complete.

Where should the money sit while I stagger it in?

Somewhere that earns more than a savings account without risking the amount, which usually means a liquid or ultra-short category with a transfer instruction into the target. Leaving it at 3% is a real cost that most comparisons ignore.

Is a systematic transfer plan the same thing?

It is the mechanism most often used for exactly this: the lump sum goes into a liquid fund and a standing instruction moves a fixed amount into the target fund each month. Economically it is staggered entry with the waiting money earning something.

Why does the return slider stop at 13%?

AMFI Best Practices Guidelines Circular 109/2023-24 caps the return used in any mutual fund illustration at 13%. A higher assumption widens the lumpsum's apparent advantage on the steady path, which is precisely the distortion this page is built to avoid.

Spread it out, or put it in at once?

If you already have the money, this is a real question with an honest answer that depends on something nobody knows in advance. Most calculators hide that by applying one constant rate, which settles the argument by assumption.

Assumptions last reviewed 20 August 2026

On your numbers

₹1.98 L

separates All in at once from Spread over 12 months

Under a steady market, investing at once ends ₹1.98 L ahead. Both reach the same average return over the window; only the order in which the market moved is different. Change the path and the answer can reverse.

All in at once: ₹37.50 L; Every rupee invested on day one, compounding for the full 10 years.
Spread over 12 months: ₹35.52 L; ₹1,00,000 a month for 12 months, then held for the rest of the period.

This is the part a single-line calculator cannot show. A model that applies one constant rate always favours the lumpsum, because money in earlier compounds longer, and it has proved nothing except that it used a constant rate. Real markets do not move evenly, and the order decides the answer.

Side by side

	All in at once	Spread over 12 months
Units bought	1200000	1136763
Average price paid	1.00	1.06
Value after the window	₹13,52,190	₹12,80,933
Value after 10 years	₹37,49,729	₹35,52,128

Your numbers

Amount you are holding

Spread it over

Then hold for, in total

Assumed return

What the market does while you deploy

The market rises evenly through the period. All three reach the same point at the end of the window, so only the order differs.

Past performance may or may not be sustained in future and is not a guarantee of any future returns. The rate is capped at 13% p.a., being the mean of 10-year rolling returns of the Nifty 50 between 1 June 2013 and 30 May 2023 (12.93%), the basis AMFI prescribes for illustrations.

Why the averaging works when it works

Spreading the money buys 1136763 units at an average price of 1.06, against 1200000 units at 1.00 for the lumpsum. A fixed rupee amount buys more units when the price is low and fewer when it is high, so the average cost per unit comes in below the average price over the period. That only helps you if the price actually spent time below where it started.

For reference, a fresh ₹1,00,000 monthly SIP over the same 12 months, with no lump sum behind it, would reach ₹12.81 L by the end of the window. That is a different question from this one, and it is the question most people are actually in: money arriving as salary has no lumpsum option.

The three paths are illustrative shapes, not forecasts, and every one of them assumes you complete the plan. The most common real outcome is that a falling market stops the instalments, which is a behaviour no model captures.

The 13% ceiling

Why this calculator stops at 13%

Many Indian return calculators let you type 20%, and some go to 30%. This one stops at 13%, which is roughly what the market has actually delivered over a decade.

What a decade actually returned

Nifty 50: 12.93%
Sensex: 12.64%
Gold, in rupees: 9.34%
10-year G-Sec: 7.20%

Mean of every 10-year rolling return between 1 June 2013 and 30 May 2023. Source: AMFI Best Practices Guidelines Circular 109/2023-24 of 1 November 2023, which sets these as the rates a mutual fund illustration in India may use. Nifty 50 at 12.93% is the highest of them, which is where the 13% ceiling comes from.

What a higher number would have shown you

Your settings above, ₹1.00 L a month for 10 years, at three different assumptions.

At 12.0%, this page

₹2.32 Cr

At 20%, elsewhere

₹3.82 Cr

1.6× this page

At 30%, elsewhere

₹7.53 Cr

3.2× this page

The gap between those figures is not a return. It is an assumption.

12.93% is the average of every ten-year stretch in that period. Some stretches were better and several were a great deal worse, and you get one of them rather than the average of all of them. So a calculator set to 20% is not being optimistic. It is quietly moving the goalposts, because a higher assumed rate makes the monthly amount you need look smaller than it is. That is the one error in this arithmetic that costs you money, and it only shows up twenty years later, when the corpus is short.

AMFI sets this ceiling for every mutual fund illustration in India. It is also the number we would have picked.

How this is calculated

Both options end up holding units in the same thing, so the only question is how many units each buys. The lumpsum buys everything on day one at one price. The staggered version buys a fixed rupee amount each month at whatever the price is that month.

The three market paths all start and end at the same place and reach the same average return over the deployment window. Only the order differs: rising puts the gains early, falling puts the fall early and recovers, steady moves evenly. After the window both hold their units and compound identically.

Isolating the path this way is the point. A model with one constant rate is a model of the steady path only, and under the steady path the lumpsum always wins, which is arithmetic rather than insight.

What this cannot tell you

The three paths are shapes, not forecasts. Real markets do not move along smooth curves, and no one knows which shape is coming. The purpose is to show that the answer is path-dependent, not to suggest which path to expect.

It assumes you complete the plan. The most common real outcome when a market falls during a deployment window is that the remaining instalments stop, which converts the strategy into something else entirely and usually a worse thing.

It ignores what the undeployed money earns while it waits. Held in a savings account at around 3%, that is a real cost of staggering which the page does not charge you for, so it is mildly favourable to spreading.

It ignores exit load, taxation on redemption, and the fact that a staggered entry creates multiple purchase dates and therefore a more complicated capital gains position later.

Is a lumpsum better than a SIP?

For money you already hold, investing it at once has beaten spreading it over most historical periods, for a simple reason: markets rise more often than they fall, so money in earlier compounds longer. On the steady path modelled here, the lumpsum wins by construction.

Under a falling market it loses, and by a material amount, because every instalment after the first buys more units for the same rupees. Switch the path selector to Falling first and watch the answer reverse. That is the honest position: on average the lumpsum, in a bad window the stagger, and nobody knows which window they are in.

Then why does every calculator say lumpsum?

Because they apply one constant rate of return. Under a constant rate the price only ever rises, so buying later always means buying higher, and the lumpsum wins with mathematical certainty. The result is not evidence about markets, it is a restatement of the assumption. Any comparison of this kind that does not let you vary the path has answered the question before you arrived.

What is rupee cost averaging, and does it work?

Buying a fixed rupee amount at regular intervals means you automatically buy more units when the price is low and fewer when it is high, so your average cost per unit comes in below the average price over the period. That is arithmetically true and it is not the same as saying you will make more money. It only helps if the price spent time below where it started. In a market that rose steadily, your average cost is below the average price and still above the price on day one.

How long should I spread it over?

Long enough to matter and short enough to finish. Six to twelve months is the range most people use, and beyond about eighteen months the cost of holding cash starts to dominate any averaging benefit. The honest way to choose is not to optimise it but to ask how large a fall you could watch without stopping, and pick a window that keeps you invested through one.

Where should the money sit while it waits?

Not in a savings account, if the window is more than a couple of months. Earning about 3% on undeployed money is a genuine cost of staggering that this page does not charge you for. A liquid or ultra-short fund with a transfer instruction into the target fund keeps the money working while the averaging happens, which is the usual way this is arranged.

Does this apply to a SIP from my salary?

No, and it is worth being clear about it. If the money arrives monthly, there is no lumpsum option and no decision to make: a SIP is simply the only shape available. This question exists only for money you already hold, such as a bonus, a maturity or a property sale. The SIP calculator is the page for the salary case.

What does the research actually say?

Studies across long histories in several markets consistently find that investing immediately beats averaging in roughly two thirds of periods, which is what you would expect from markets that rise more often than they fall. The same studies find that averaging reduces the dispersion of outcomes, including the worst ones. So immediate investment has the better average and averaging has the better bad case, which is a trade rather than a winner.

What is the honest way to decide?

By asking what you would do if the market fell 25% the month after you invested. If the answer is that you would hold, the arithmetic favours investing at once and you should. If the answer is that you would sell, or that it would keep you awake, spreading it costs a little expected return and buys the thing that actually determines your outcome, which is staying invested. That is a question about you and not about the market.

Questions people ask about this

For money you already hold, investing at once has historically produced more in about two thirds of periods, because markets rise more often than they fall. Spreading it produces a narrower range of outcomes, including a better worst case. Which matters more depends on how you would behave in a fall.

Related calculators

Talk to the desk

The right answer depends on what you would do in a fall.

The arithmetic is only half of it, and the half that decides most outcomes is whether the plan survives a bad quarter. Bring the amount you are holding and we will talk about both.

Talk to a human

Mutual Fund investments are subject to market risks; read all scheme-related documents carefully. Past performance does not guarantee future returns.

Calculator outputs are indicative projections on assumptions you select, not assurances, and not a projection of the performance of any scheme. The market paths shown are illustrative shapes, not forecasts.