What this calculator does to the number you type
Most SIP calculators hand you one big figure and leave you to trust it. This one works your plan out month by month, the way the money actually moves, and every number on the page comes from that same run — the headline, the two charts, the year-by-year table and the CSV you can download. They cannot drift apart from one another, because there is only one calculation.
Here is the sequence it walks through, for every month of the term you set. Your instalment goes in at the start of the month. If you have asked for a withdrawal, it comes out next. Whatever is left then grows for that month. At the end of each twelfth month, if you have switched on the annual increase, your instalment steps up for the year ahead.
That ordering matters more than it looks. Money paid in at the start of a month earns a month of growth that the same money paid in at the end would not. Over ten years at 12% that single convention is worth about ₹11,500 on a ₹5,000 instalment — not enormous, but it is the difference between two calculators that both look right and disagree with each other.
The other convention worth stating plainly: the annual return you type is divided by twelve to get a monthly rate. Type 12% and the calculator uses 1% a month, which compounds to 12.68% over a year, not 12%. This is what fund houses and AMFI’s own calculators do, so the figures here line up with theirs. It also means the headline number is very slightly more generous than the percentage you typed would suggest, and you should know that rather than discover it.
The return is an assumption, and it is doing all the work
Everything else on the page is arithmetic. The return is a guess, and it is the guess that decides the answer. It is worth seeing how much of the answer it decides.
Between a cautious 8% and an optimistic 14% there is ₹3,89,629 of difference on an identical ₹5,000 instalment. That gap is larger than the entire ₹3,60,000 you would have paid in over the first six years. Nobody can tell you which of those two numbers is right, because it depends on what markets do over a decade that has not happened yet.
Because that gap decides everything, the calculator does not make you check it by hand. Under the summary there is a strip showing the same plan at four assumed returns — four points below what you typed, two below, your figure, and two above — recalculated every time you change anything. Read it as the range your plan lives in rather than treating the headline as the answer.
The test worth applying: if the plan only works at the optimistic end of that strip, it is not a plan, it is a hope. If it works at the pessimistic end, everything above that is a bonus. And if you want to come back to a particular set of assumptions, Copy a link to this plan puts every input in the address, so you can bookmark it or send it to whoever you are deciding with.
One more thing the percentage has to absorb: the fund’s expense ratio comes out of returns before you ever see them. If a fund’s gross return is 12% and its expense ratio is 1.2%, what reaches you is closer to 10.8%. Type the return you expect to receive, not the return the fund advertises. This calculator has no way of knowing which one you meant.
Rupee cost averaging, without the sales pitch
The standard argument for a SIP is that investing a fixed amount each month buys more units when prices are low and fewer when they are high, so your average cost per unit ends up below the average price over the period. That is arithmetically true, and it is a real advantage over trying to time your entry.
What the sales version leaves out is that this calculator cannot show it to you. A constant assumed return has no ups and downs in it, so there is nothing to average across. The smooth curve on the chart is a convenience, not a forecast — real markets do not deliver 1% a month, twelve months a year, for ten years.
The practical consequence is sequence risk, and it cuts both ways. Two decades with identical average returns can leave you in very different places depending on when the bad years arrive. Early losses hurt a lump sum badly but hurt a SIP much less, because your later instalments buy in cheaply. Late losses are the opposite: by year nine most of your money is already invested, and a bad year then lands on the whole pile rather than on a small one.
This is the honest case for a SIP, and it is a good one: it removes the decision you are worst at making, which is when to buy. It does not remove the risk of losing money, and no calculator on any website can promise that it will.
Raising your SIP each year beats hunting for a better fund
The single change with the largest effect on the final number is not the fund you pick. It is increasing the instalment as your income grows — switch on Increase my SIP every year and watch what happens.
A 10% annual step-up turns ₹11,61,695 into ₹16,87,163. That is ₹5,25,468 more, and it required no better fund, no cleverer timing and no higher assumed return. To get the same improvement by performance alone you would need roughly 17% a year instead of 12% — a difference you cannot arrange, whereas a 10% raise on a ₹5,000 instalment is ₹500 in the first year.
The instalment does climb: starting at ₹5,000 with a 10% increase, you are paying ₹11,795 a month in the tenth year. The calculator tells you that figure in plain words underneath the result, because a plan you cannot actually afford in year eight is not a plan either. If the final instalment looks unrealistic, lower the step-up rather than discovering the problem in year eight.
What ₹11 lakh will actually buy in ten years
A number ten years out is not worth what the same number is worth today, and this is the single most common way people mislead themselves with a calculator. Leave Show what it is worth in today’s money switched on and you get both figures.
₹11,61,695 in ten years, with inflation at 6%, buys what ₹6,48,684 buys today. You have not lost anything — you genuinely have the larger sum — but if you are saving towards something whose price also rises, the smaller figure is the one that answers your question.
The 6% default is deliberate. The Reserve Bank of India’s medium-term target for consumer price inflation is 4%, within a tolerance band of 2% to 6%. Six per cent is therefore the pessimistic edge of the official band rather than a wild guess, and it keeps the calculator from flattering itself. If you are saving for something that inflates faster than the general index — school and college fees are the usual example, and medical costs the other — put a higher number in.
The tax that arrives at the end, and the exemption most people forget
Nothing is taxed while a SIP is running. The bill arrives when you redeem, and for equity mutual funds held longer than twelve months the current rule is 12.5% on long-term capital gains above ₹1.25 lakh in a financial year, for transfers made on or after 23 July 2024.
The If taxed as equity figure on the results applies exactly that: it takes your gains, subtracts the ₹1.25 lakh exemption, charges 12.5% on the rest, and shows what would be left. On the default plan that is about ₹54,587 of tax on ₹5,61,695 of gains.
Two honest caveats about that figure, because it is an estimate and should be read as one. It assumes you sell everything in a single financial year, which is the worst case; the ₹1.25 lakh exemption renews annually, so redeeming across two or three years can legitimately reduce the bill. And it assumes an equity fund. Debt funds are taxed differently, and if you are running a SIP into a debt or hybrid scheme this line does not apply to you.
What the calculator cannot do is work out which units you are selling. A SIP buys units every month, so a ten-year SIP is a hundred and twenty separate purchases, each with its own holding period and cost. Real redemption is first-in-first-out at unit level, and your fund house’s capital gains statement is the only accurate source. Treat the number here as the right order of magnitude for planning, and the statement as the truth for filing.
Moving a lump sum in gradually, and what an STP really costs
If a large sum has just landed — a bonus, a maturity, a sale — putting all of it into an equity fund on a single day means one day’s price decides a lot. A Systematic Transfer Plan is the usual answer: park the money in a low-risk fund and move a fixed amount across at regular intervals. Switch on Move a lump sum in gradually (STP) and the calculator runs both funds side by side.
Two things about this are worth being blunt about, because most STP calculators get the first one wrong. An STP is not new investment. The money is already yours; it is changing pocket, not arriving. So the parked amount is counted in “You put in” exactly once, on day one, and the transfers themselves add nothing to it. A calculator that adds each transfer to your total invested will tell you that you invested far more than you did, and will understate your return to match.
The second: the source fund keeps earning while it drains, which is the entire reason to park it somewhere rather than a current account. Move ₹25,000 a month out of ₹6,00,000 sitting at 6.5% and you will transfer about ₹6,40,779 in total — more than you parked, because the balance goes on growing between transfers. The calculator reports the actual amount moved, and tells you the month the source runs dry.
Slower is not automatically less, either, which surprises most people. At ₹25,000 a quarter the source takes until month 91 to empty and moves about ₹7,51,976, because the money spends far longer earning in the source fund before it leaves. At ₹25,000 every six months it never empties at all inside ten years: twenty transfers is exactly ₹5,00,000, and ₹4,32,268 is still sitting there at the end. The tool says so rather than quietly leaving it out of the total.
And the honest headline: against putting the whole sum in on day one, phasing in usually finishes slightly behind. On the default settings it ends about ₹1,04,330 short. That is not an argument against it. A constant assumed return can only ever rise, so day-one investing wins by construction in this model; the protection an STP actually buys you shows up in the years the model cannot draw, when the market falls after you invest. The calculator prints the comparison both ways and lets you decide which risk you would rather carry.
Taking money out, and the year a withdrawal plan runs dry
Switch on Take money out regularly (SWP) for the retirement-shaped question: if I take a fixed amount out every month, how long does the money last? It is the same simulation, with the withdrawal removed from the balance in the month it happens. Because it is a switch rather than a mode, it combines with everything else — you can run a step-up SIP, an STP and a withdrawal at once if that is genuinely your situation.
That last detail is the whole point. Money you take out in year three is not there to grow in years four to ten, and the loss compounds. Subtracting the total withdrawn from the final figure — which is what a surprising number of calculators do — overstates the result badly. On a ₹5,000 SIP with a ₹1,000 monthly withdrawal over ten years the gap between the two methods is over a lakh.
If the withdrawal is larger than the fund can sustain, the calculator says so: it names the year and month the balance hits zero, and stops there. It will not show you a negative fund value, because a fund cannot hold less than nothing, and a calculator that prints a negative balance is telling you something that cannot happen.
Used sensibly, this is the tab that tells you whether a corpus is big enough. Put in what you have, set the withdrawal you need, and see whether the money outlives the term. If it does not, the honest options are a bigger corpus, a smaller withdrawal, or a longer accumulation period — and you can test all three in about a minute.
What this calculator will not tell you
It does not know which fund to buy, and it will not suggest one. It has no NAV data, no fund performance, no ratings, and no opinion about active versus index.
It does not model exit loads, which many equity funds charge on units redeemed inside a year, nor stamp duty on purchase, nor the expense ratio — you have to fold that into the return you type, as described above.
It assumes a perfectly constant rate. Real returns arrive unevenly, and the order they arrive in changes the outcome even when the average is identical.
It cannot see your other money: your emergency fund, your loans, your insurance, your PPF or EPF balance. A SIP that is technically optimal while you carry a credit card balance at 40% is not optimal.
And it is not advice. It is arithmetic on numbers you chose, run in your browser. Nothing you type is sent anywhere — the whole calculation happens on your device, and closing the tab is all it takes to erase it.
Questions people ask when planning a SIP
Is 12% a reasonable return to assume for Indian equity?
It is the figure most Indian calculators default to, and long-run broad-market history is roughly in that neighbourhood before costs. That is not a promise about the next ten years. Run 8% as well and see whether your plan still works; if it does, you have built in a real margin.
Why does the total not match my fund house’s calculator exactly?
Almost always one of three conventions. Whether the instalment is counted at the start or the end of the month; whether the annual rate is divided by twelve or converted to a true monthly equivalent; and how partial months near the end are handled. This calculator uses start-of-month and divide-by-twelve, and says so on the results, so you can see which convention is in play. Differences of a few thousand rupees over ten years are conventions, not errors.
Should I invest a lump sum or start a SIP?
If the money is already sitting in your bank account, historically a lump sum has more often come out ahead, simply because it spends longer invested. A SIP wins on behaviour rather than arithmetic: it is easier to keep going, and it removes the timing decision. You can test all three here: Start with a lump sum invests it on day one, Move a lump sum in gradually (STP) phases it in, and running neither gives you the plain SIP.
What happens if I stop paying for a few months?
Nothing breaks. Your existing units stay invested and keep growing; you simply stop adding. Most fund houses will cancel a SIP mandate after a few consecutive failed instalments, and you would need to start a fresh one. This calculator assumes an unbroken run, so a real gap will leave you a little behind the figure shown.
Is a longer SIP really that much better?
Dramatically, and it is the least intuitive thing on this page. The same ₹5,000 a month at 12% builds ₹11,61,695 over ten years and ₹49,95,740 over twenty. You paid in twice as much and ended with more than four times as much, because in the second decade the growth is compounding on a balance the first decade built. Time is the input you can least afford to waste and the one that costs nothing.
Can I use this for a recurring deposit or PPF?
The arithmetic of a fixed monthly contribution is the same, so the shape of the answer will be right. But those products have their own compounding rules and fixed, declared rates, so use the RD and FD maturity calculator or the PPF calculator for an accurate figure. For a one-off deposit with no monthly addition, the compound interest calculator is the closer fit.
How SIP growth is calculated
A SIP is a series of equal investments, each of which grows for the time it stays invested. The maturity value uses the future-value-of-a-series formula:
FV = P × [((1 + i)n − 1) / i] × (1 + i)
where P is the monthly investment, i is the monthly rate of return (the expected annual return divided by 12), and n is the total number of monthly installments. The first installment compounds for the whole period, the last for only a month — the formula sums all of these.
Sources & further reading
- Securities and Exchange Board of India (SEBI) — the regulator for mutual funds; its investor-education material explains SIPs, expense ratios and the risks behind market-linked returns.
- Association of Mutual Funds in India (AMFI) — daily NAVs, category-wise historical returns and the standard disclosures fund houses must make.
Mutual fund investments are subject to market risk. The expected-return figure you enter is an assumption, not a guarantee — past performance does not indicate future results, and this projection ignores expense ratios, exit loads and capital-gains tax. Read the scheme information document and consult a SEBI-registered investment adviser before investing.
