Step-up vs regular SIP: the real difference
How much a yearly increase actually adds to your corpus, with side-by-side numbers.
A step-up SIP and a regular SIP can start at the exact same monthly amount and still end up producing very different corpuses — the only difference is what happens to the contribution in the years after that. Here’s what that difference is actually worth, and what it would take a regular SIP to catch up.
Same starting point, a very different trajectory
Both start at ₹15,000/month, 12% expected return, 15-year horizon. The regular SIP stays at ₹15,000/month for all 15 years, reaching ₹74,93,703. The step-up SIP, using the real computeStepUpSipformula with a 10% annual step-up, starts identically at ₹15,000/month but is contributing ₹56,962/month by year 15 — reaching ₹1,28,96,806, 72% more than the regular SIP, from the same starting contribution.
Model a SIP that increases every year in line with your rising income.
Project the future value of your monthly SIP investments.
What it would take a regular SIP to match it
Turning the comparison around: what flat monthly amount would a regular SIP need, from day one, to reach that same ₹1,28,96,806 corpus over the same 15 years at the same 12% return?
Using the real computeSip formula solved for the target corpus: a regular SIP would need to start at ₹25,815/month— not ₹15,000 — and hold that amount flat for all 15 years to land on the identical ₹1,28,96,806. That’s 72% higher than the step-up SIP’s starting contribution, which is exactly the practical problem a step-up SIP is designed to solve: most people don’t have ₹25,815/month of spare capacity in year one of a 15-year plan, only by the time their income has actually grown into it.
Why it isn’t just “free” extra return
There’s a counter-intuitive wrinkle worth knowing: the step-up SIP above invests ₹57,19,047 in total over 15 years to reach its ₹1,28,96,806 corpus. The equivalent flat ₹25,815/month regular SIP invests only ₹46,46,752total — nearly ₹11 lakh less — to reach the exact same corpus.
The reason is compounding time, not efficiency: every rupee contributed early has more years left to grow than a rupee contributed late. The regular SIP front-loads its (larger) contributions, so more of its total investment gets the full 15 years to compound. The step-up SIP’s largest contributions arrive latest, when there’s the least time left for them to grow — so it needs to contribute more total rupees to close the same gap. A step-up SIP isn’t a mathematically superior route to a given corpus; it’s a practical one, built around matching your contribution to your income as it actually arrives rather than requiring the full commitment upfront.
All figures are indicative and for educational purposes only — not financial advice.
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