What is Step-up SIP?
A systematic investment plan whose instalment rises by a fixed percentage each year, usually to track income growth.
Each year is its own twelve-month annuity at that year's instalment, compounding for the years remaining. The advantage over a flat SIP is large and almost entirely back-loaded. Most of it comes from instalments you have not started making yet.
Not to be confused with Flat SIP
A flat SIP keeps the same instalment for the whole term. Stepping up by 10% a year roughly doubles the outcome over fifteen years on the same starting amount.