What Changes a SIP's Result Most? Seven Calculations for ₹10,000 a Month

Every example below is a SIP of ₹10,000 a month. Growth rates are assumptions, written as a yearly rate; nobody knows the rate in advance, so treat each result as 'if the rate were this', never as a forecast. We use the same method as our free SIP calculator: each instalment goes in at the start of the month, and the yearly rate is turned into a monthly rate as (1 + yearly rate) to the power of 1/12, minus 1.

A lakh is one hundred thousand rupees and a crore is a hundred lakh. All the arithmetic below is ours, and you can repeat it on the calculator.

₹10,000 a month for 15 years puts in ₹18 lakh. At an assumed 8% a year it becomes about ₹33.98 lakh, at 10% about ₹40.16 lakh and at 12% about ₹47.59 lakh.

A single percentage point matters. At 11% instead of 12%, the 15-year result is about ₹43.71 lakh, which is ₹3.88 lakh (about 8%) lower. Over 20 years the same one-point gap is larger in rupees: about ₹81.56 lakh against ₹91.99 lakh, a difference of about ₹10.43 lakh.

The longer the period, the more a small difference in the rate is worth. That also means a result shown to the last rupee can look more certain than it is.

Keep the amount and the 12% assumption the same and change only how long the SIP runs:

15 years: ₹18 lakh put in, about ₹47.59 lakh.

10 years: ₹12 lakh put in, about ₹22.40 lakh.

5 years: ₹6 lakh put in, about ₹8.11 lakh.

Cutting five years takes a third off the money put in (₹18 lakh to ₹12 lakh) but more than half off the result (₹47.59 lakh to ₹22.40 lakh, down about 53%). Money put in early has more time to compound, so the early instalments carry a lot of the final figure. The same pattern holds at 10%: about ₹40.16 lakh for 15 years against ₹20.15 lakh for 10.

Raising the instalment every year changes the picture. Still ₹10,000 to start, 15 years, 12% assumed:

No raise: ₹18.00 lakh put in, about ₹47.59 lakh (about 2.64 times the money put in).

5% raise each year: ₹25.89 lakh put in, about ₹61.91 lakh (about 2.39 times).

10% raise each year: ₹38.13 lakh put in, about ₹82.75 lakh (about 2.17 times).

A 10% yearly raise lifts the final amount by about 74%, but it more than doubles what you put in, and each rupee put in ends up as fewer rupees. The raise helps because you invest more, not because the money works harder. If a raise would strain the budget in a later year, that is worth knowing before choosing the percentage.

Suppose the SIP runs 15 years at 12% assumed, but no instalments are paid for the twelve months of year 5. Skipping ₹1.2 lakh of instalments leaves about ₹43.63 lakh instead of ₹47.59 lakh, which is about ₹3.97 lakh less. The gap is more than three times the money not put in, because those instalments would have had ten more years to grow.

Now suppose the SIP stops after 10 years but the money stays invested for five more years at the same 12%. It reaches about ₹39.48 lakh, against ₹47.59 lakh if the instalments had continued to year 15 (about ₹8.11 lakh less).

AMFI's own table gives context for stopping. From April to September 2026, 351.48 lakh new SIPs were registered and 307.43 lakh were discontinued or completed their tenure, about 87 for every 100 registered. AMFI notes that the 'discontinued' figure includes SIPs that reached their planned end, and that three failed monthly instalments in a row count as ceased, so it is not a count of people who gave up.

The arithmetic can also be run in reverse. To reach ₹1 crore after 15 years, the first-year monthly instalment would need to be about:

₹29,431 at an assumed 8% a year

₹24,899 at 10%

₹21,011 at 12%

Over 10 years the figure is higher: about ₹49,638 a month at 10% and ₹44,636 at 12%. The gap between 8% and 12% for the same target is about ₹8,400 a month over 15 years. This is a way to see how much the unknown rate moves the required amount, not a statement of what amount is right for anyone.

The ₹47.59 lakh at the end of 15 years is a number in future rupees. If prices rise 6% a year for 15 years, things cost about 2.4 times as much, so ₹47.59 lakh would buy what about ₹19.86 lakh buys today (our arithmetic). At 5% inflation the figure is about ₹22.89 lakh.

Inflation over the next 15 years is also unknown, so the figure is only a way to compare. Comparing future amounts with today's prices is a habit worth having when you read any SIP result.

Assumptions are one thing; history is another. Using AMFI's published prices to 31 October 2026, we worked out the annual return of a monthly SIP for every possible start month with a full 15 years of history, across funds of each type (closed funds included). These are past results:

Large cap funds: 990 SIPs from 21 funds. Lowest start month about 7.4% a year, middle about 12.9%, highest about 17.1%.

Flexi cap funds: 1,140 SIPs from 23 funds. Lowest about 5.9% a year, middle about 14.7%, highest about 19.2%.

Nifty 50 index funds: 449 SIPs from 9 funds. Lowest about 9.9% a year, middle about 12.2%, highest about 14.3%.

None of those 15-year SIPs ended below the money put in. The 12% used above falls inside each range, but the highest and lowest start months were several points apart even over 15 years, and these windows overlap and come from one period of history. Past results do not predict future ones.

AMFI reports that SIPs collected ₹32,490 crore in September 2026, through about 10.89 crore outstanding SIP accounts, and that SIP assets under management were about ₹17.86 lakh crore. An account is not a person: one investor can hold several. These totals describe the industry, not what any one SIP will do.

None of these seven calculations says what to do. They show which inputs move a result most (the rate, then the time, then how much goes in) and that the future rate is the one number nobody can supply. The useful step is to run your own amount and period at a low, a middle and a high assumed rate, and read the range instead of a single figure.

Our SIP calculator does that, and shows what real fund history looked like over comparable periods, with the assumption and the past data labelled separately. FinResp analyses. You decide.