SIP calculator with step-up, inflation and post-tax corpus
Most SIP calculators stop at the final corpus number. This one continues: it applies inflation to show what the corpus is worth in today’s money, and it applies LTCG tax to show what you actually keep.
Year-by-year breakdown
| Year | Monthly SIP | Invested this year | Cumulative invested | Year-end balance |
|---|
How the formula works
A flat SIP (no step-up) follows the future-value-of-annuity formula:
FV = P × [ ((1 + i)n − 1) / i ]
where:
P = monthly investment
i = monthly return rate (annual rate ÷ 12)
n = number of months
For ₹10,000 a month over 10 years at 12% annual return, i = 0.01
and n = 120, which gives a future value of about ₹23 lakh.
Of that, ₹12 lakh is your invested principal; the remaining ₹11 lakh is
compounding.
With a step-up SIP, the monthly amount grows each year by your step-up percentage, so this calculator iterates month by month rather than using the closed-form formula above.
Worked example
Start with ₹10,000 a month, step it up by 10% every year, assume 12% annual return, and run it for 15 years. The calculator shows:
- Year 1 monthly SIP: ₹10,000. By year 15: ₹35,950.
- Total invested over 15 years: about ₹38.1 lakh.
- Final corpus (nominal): about ₹86 lakh.
- Real value at 6% inflation: about ₹36 lakh in today’s money.
- Post-tax (after LTCG): roughly ₹80 lakh.
The drop from ₹86 lakh nominal to ₹36 lakh in real terms is the main reason inflation belongs in any long-horizon plan.
FAQs
What is a SIP and how does this calculator work? ▾
A Systematic Investment Plan (SIP) is a way of investing a fixed amount in mutual funds at regular intervals (usually monthly). This calculator simulates your SIP month by month at the expected return rate you enter, and shows the year-end balance, total invested, gains, inflation-adjusted real value, and post-tax corpus.
What is a step-up SIP? ▾
A step-up SIP raises your monthly contribution each year by a fixed percentage. A 10% annual step-up roughly tracks salary growth and produces a much larger corpus over 15-20 years than a flat SIP, while never feeling like a sudden jump in any single year.
Why does this calculator include inflation? ▾
A ₹1 crore corpus 25 years from now will not buy what ₹1 crore buys today. At 6% inflation it is worth roughly ₹23 lakh in today's money. The "real value" figure here is that adjustment, so you can plan against what the corpus will actually be able to purchase.
How is tax on SIP returns calculated in India? ▾
For equity mutual funds, gains on units held over 1 year are Long-Term Capital Gains (LTCG). Following the 2024 Union Budget, LTCG above ₹1.25 lakh per financial year is taxed at 12.5%. This calculator applies that rule once at the end of the period as a simplification; actual SIP tax treatment is per-tranche based on each instalment's holding period, which is more conservative for long horizons.
What return rate should I assume? ▾
Long-term equity mutual fund CAGR has historically been in the 10-14% range, but past returns do not guarantee future ones. 10-12% is a reasonable working assumption. Worth trying a few rates: the gap between 10% and 12% over 20 years is bigger than it intuitively feels.
Are these returns guaranteed? ▾
No. Mutual fund returns are market-linked and vary year to year. The calculator shows what your inputs imply if the assumed rate actually held over the full period; real returns will differ. Treat the output as a planning aid, not a forecast.