How this SIP calculator works
A SIP (systematic investment plan) invests a fixed amount in a mutual fund every month. A SIP calculator estimates what those instalments could grow to.
The usual calculator assumes every month earns exactly the same return. Markets don't work that way: 2020 began with a crash and ended with a rally, and the order of good and bad years changes what you end up with. This calculator keeps the average return you choose but replays real month-to-month swings from Indian index funds since 2013, 5,000 times, and reports the spread of results.
- Middle outcome: half the simulated paths end above it and half below.
- 1 in 10 below: a bad but plausible result. Only one path in ten does worse.
- 1 in 10 above: a good result. Only one path in ten does better.
The fixed-rate SIP formula
For comparison, a fixed-rate calculator uses
M = P × ((1 + i)n − 1) / i × (1 + i)
where P is the monthly amount, i the monthly rate (annual rate ÷ 12) and n the number of months. ₹10,000 a month for 15 years at 12% gives about ₹50.5 lakh on ₹18 lakh invested. The calculator above shows that figure next to its own range, so you can see how much the single number leaves out.
Questions
How is this different from other SIP calculators?
Most SIP calculators grow every instalment at one fixed rate, such as 12% a year, and show a single number. Real markets rise and fall. This calculator replays the month-to-month swings of Indian index funds 5,000 times and shows the range: the middle outcome, a result that only 1 in 10 paths falls below, and one that only 1 in 10 beats.
What is a step-up SIP?
A step-up (or top-up) SIP raises the monthly amount by a fixed percentage once a year, for example 10% with each salary hike. Because the larger instalments come later, step-up raises the final value much more than it raises the total invested.
What return should I expect from an equity SIP?
No one knows. Indian large-cap equity has compounded at roughly 11 to 13% a year over long periods, but with years of losses along the way. Try a lower figure, such as 8%, to see a weaker decade.
What does "in today's money" mean?
It is the middle outcome adjusted for 6% annual inflation, so you can compare it with prices today. ₹1 crore in 20 years buys roughly what ₹31 lakh buys now.
Is my data sent anywhere?
No. The simulation runs in your browser. Nothing you type is sent to a server.