How the monthly amount is found
The starting balance grows at the monthly rate. The rest of the goal is funded with equal monthly deposits that also earn interest. If the rate is 0, monthly = (goal − already saved) ÷ months.
This is an estimate. Real accounts skip months, change rates, and charge fees. It is not investment advice.
Worked example
To have $6,000 in 18 months with $500 already saved and no interest, you need about $306/month. At 3% annual interest the required deposit is a little lower because the balance grows.
A high-interest savings account rate changes. If you miss a month, the later deposits have to be larger. This is not investment advice.
Common questions
What rate should I use?
A high-interest savings account rate, not a stock-market guess, if you need the money on a date.
What if I already have more than the goal?
The monthly amount is 0. You are there.