How much do you need to invest for it?

It starts with what the goal costs today and raises that by inflation for each year until you need the money. It then works out the monthly investment that grows to that amount at your expected return, after counting what you have already saved.

It depends on how long you have. For goals under three years away, assume what safe investments earn, around 6% to 7%. For three to seven years, a mix of debt and equity might earn 8% to 10%. For longer goals invested mostly in equity, 10% to 12% is a common planning figure. None of these is promised.

A SIP that rises by a fixed percentage every year, usually in line with your salary. Because later instalments are larger, you can start with a much smaller amount than a flat SIP needs for the same goal.

A cost that rises 10% a year triples in about twelve years. Planning for today's price leaves a goal far short, which is why the calculator shows the future cost alongside the SIP.