Reaching a savings target is mostly about consistency. If you know the goal, your timeline, and a realistic rate of return, you can work backward to the monthly amount that gets you there.
How the monthly amount is found
The calculator grows your current balance forward at the expected return, then solves for the steady monthly contribution whose compounded value covers the rest of the goal. A higher return or a longer timeline lowers the monthly amount you need.
Returns aren't guaranteed, so treat the result as a plan, not a promise. For short timelines, a conservative return assumption is safer.