SIP Top-Up Calculator: Investing in Mutual Funds through Systematic Investment Plan (SIP) is very popular. Systematic Investment Plan (SIP) is a better way to invest to grow your wealth in the long term. In this, a fixed amount has to be invested every month which is invested in the mutual fund scheme. Top-Up SIP is also a facility available in mutual funds, through which you can increase your existing SIP by some amount every year. This increase can either be a few percent of the SIP amount or it can be a fixed amount. Advisors also advise that taking top up as your income increases is a wise option. As your financial condition improves or salary increases, you can increase the investment every year.