How a step-up SIP compounds
A step-up SIP raises your monthly instalment by a fixed percentage every year, so your investing keeps pace with your income instead of being frozen at whatever you could afford when you started. Over a long horizon the difference against a flat SIP is dramatic.
Formula
Each year: instalment = previous instalment × (1 + step-up%), compounded monthly
- The first twelve instalments use your starting amount
- Every twelfth month the instalment increases by the step-up percentage
- All instalments continue compounding at the expected return until the end
How much difference a 10% step-up makes
Start at ₹10,000 a month for 15 years at 12% and a flat SIP reaches about ₹50.5 lakh on ₹18 lakh invested. Add a 10% annual step-up and the same starting instalment reaches roughly ₹86.9 lakh on ₹38.1 lakh invested.
You invested more, of course — but you also began investing more only as your income grew. By the final year the instalment has risen to about ₹37,975 a month, which usually feels no harder than ₹10,000 did fifteen years earlier.
Match the step-up to your expected raises
A step-up only works if you can actually sustain it. Setting it at or slightly below your typical annual increment keeps the plan realistic; setting it at 15% when raises average 7% guarantees you will abandon it in a few years.
If your income is irregular, a smaller step-up with occasional lump sums may suit better than a fixed annual increase.
Setting it up in practice
Many fund houses and platforms offer a step-up or top-up SIP that increases the instalment automatically, either by a percentage or a fixed rupee amount. Where it is not available, the same effect comes from starting a small additional SIP each year and leaving the original running.
Check that your bank mandate limit is high enough to cover the increased instalments in later years, otherwise the step-up will fail silently once it crosses the approved amount.
What the projection assumes
The calculation uses a constant return, no missed instalments, and no charges. Real returns fluctuate, funds deduct an expense ratio, and tax applies when you redeem.
Treat the output as a planning figure rather than a promise, and re-run it every couple of years with your actual instalment and portfolio value.
Example: ₹10,000 a month, 10% step-up, 15 years at 12%
- Starting instalment
- ₹10,000
- Annual step-up
- 10%
- Instalment in year 15
- ≈ ₹37,975
- Total invested
- ≈ ₹38.13 lakh
- Projected value
- ≈ ₹86.9 lakh
- Flat SIP for comparison
- ≈ ₹50.5 lakh
The step-up adds about ₹36 lakh to the final corpus for roughly ₹20 lakh of extra contributions — the balance comes from those larger instalments compounding for the remaining years.