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 computeStepUpSip formula 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 ₹46,46,752 total (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 doesn’t beat a regular SIP on math alone: its real advantage is practical, 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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