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.
A worked example
Say you want $20,000 in five years, you already have $2,000 saved, and you expect a 4% annual return. That $2,000 grows to about $2,440 on its own, leaving roughly $17,560 to come from contributions — which works out to about $265 a month.
Assume no growth instead (money in a checking account) and the required amount rises to about $300 a month, since nothing is helping you along. The gap between those two numbers is exactly what a modest return buys you.
The levers you control
Three things change the monthly number: the size of the goal, the timeline, and the expected return. Extending the deadline or accepting a slightly higher (and riskier) return lowers the monthly amount; a nearer deadline raises it sharply. For goals only a year or two away, keep the money somewhere safe and assume little to no growth; for goals a decade out, investing becomes reasonable.
The most reliable way to actually hit the target is to automate the transfer on payday, before the money is available to spend. Treating the contribution like a fixed bill removes the monthly decision that derails most savings plans.