What is a step-up SIP?
A step-up (or "top-up") SIP raises your monthly instalment by a fixed percentage every year, usually in line with an expected rise in income. Instead of investing a flat amount for the full period, you start smaller and let your contribution grow alongside your salary.
Because later instalments are larger, more money spends time compounding at a higher base — so a step-up SIP can build a noticeably larger corpus than a flat SIP of the same starting amount, without a big jump in what feels affordable early on.
Each year's SIP = P × (1 + s)y − 1, compounded monthly at rate r
P — starting SIPs — annual step-upy — year numberr — monthly return