Project the future value of a one-time and monthly investment.
The one-time amount grows using compound interest (future value = P × (1+r)^n), and the monthly additions grow using the future value of a growing monthly annuity — the same math behind SIP calculators. The two are added together.
It's similar, but this tool also lets you add a one-time lump-sum investment alongside the recurring monthly amount, which is useful when you're combining existing savings with new monthly contributions.