SIP Calculator with Inflation and Step-Up

What your corpus is really worth

A SIP calculator that tells you ₹10,000 a month becomes ₹1 crore in twenty years is telling you something almost useless on its own, because a crore in twenty years does not buy what a crore buys today. Very few calculators adjust for that. This one does, and the line is on by default.

Set the inflation rate to whatever you consider realistic, commonly 5% to 6% for India, and the summary adds a line showing the corpus in today's money. At 6% inflation, a crore in twenty years has roughly the buying power of ₹31 lakh now. That is not a reason to invest less. It is the number you should be planning against, and the year by year table carries it too so you can see the gap widen.

The step-up, which most people underestimate

A step-up SIP raises the monthly amount by a fixed percentage each year, usually tracking a salary rise. It costs very little in the early years and changes the outcome more than picking a slightly better fund: a 10% annual step-up can lift the final corpus by half or more over fifteen years compared with a flat SIP. Set it to 0 to compare.

And the lumpsum you would have needed instead

Under the summary the tool shows the single amount you would have to invest today, at the same return, to reach the same figure. It is a quick way to judge whether a windfall is better put in at once or spread out.

Returns are a projection, not a promise. Plan with a conservative number and treat anything above it as a bonus.

How SIP returns are calculated

A systematic investment plan invests a fixed amount every month, and each instalment compounds from its own date. The calculator applies the standard future-value-of-annuity method using the effective monthly rate derived from your annual return assumption:

Why step-up SIPs are powerful

Most people’s income grows every year, so a fixed SIP quietly shrinks as a share of earnings. A step-up SIP raises the instalment by a fixed percentage annually. The effect is large: ₹10,000 per month at 12% for 15 years builds about ₹50 lakh, but the same SIP with a 10% annual step-up builds roughly ₹80 lakh, with the extra contributions concentrated in later, higher-earning years. Try both above and compare the totals.

Reading the results honestly

The projection assumes a smooth constant return, but markets deliver lumpy returns around an average. Over long periods the smooth model is a reasonable planning tool; over 2 or 3 years it can be badly wrong in either direction. That is why SIPs suit goals at least 5 to 7 years away. Also note the wealth gained figure is pre-tax: Indian equity fund gains above the annual exemption are taxed at the prevailing LTCG rate on redemption.

The lumpsum comparison

Under the result, the tool shows the one-time investment that would reach the same value at the same return. This is useful when you receive a bonus and wonder whether to invest it at once or spread it out: mathematically, investing earlier wins if returns are positive on average, while SIPs win on discipline and rupee-cost averaging in volatile markets.

Worked example: planning a ₹1 crore goal

Say you want ₹1 crore in 15 years for a child’s education. At 12%, a flat SIP needs about ₹20,000 per month. With a 10% annual step-up you can start at roughly ₹13,000 and reach the same goal, because your contributions grow with your income. Try it above: set the target period, adjust the monthly amount until the projected value crosses ₹1 crore, then add the step-up and watch the required starting amount fall. Planning backwards from the goal is the single most useful way to use this tool.

What the projection deliberately leaves out

Expense ratios are already inside a fund’s published returns, so do not subtract them again. Exit loads apply only to early redemptions. Taxes, however, are not included: long-term equity gains above the annual exemption are taxed on redemption, so a goal-based plan should either target a slightly higher corpus or assume a rate about half a point lower than your gross expectation. And remember rebalancing: as the goal approaches, shifting from equity to debt protects the corpus from a badly timed crash in the final years.