Reaching a $50,000 goal in 5 years with $5,000 already saved at a 4% return takes a deposit of $662.08 a month. The monthly saving required to hit a target is a future-value problem solved in reverse: grow what you already have to the deadline, subtract it from the goal, and find the level deposit whose compounded sum covers the rest.
Suppose you put the default values into Savings Goal Calculator:
Plug those into the formula PMT = (FV − P(1+r)^n) · r / ((1+r)^n − 1) and the result is:
| In how long? | Save monthly | Total contributions |
|---|---|---|
| 3 years | $1,161.91 | $41,829 |
| 5 years | $662.08 | $39,725 |
| 10 years | $288.94 | $34,672 |
| 15 years | $166.19 | $29,915 |
| 20 years | $106.02 | $25,446 |
The calculator inverts the future-value-of-an-annuity formula, the same method behind Bankrate's savings goal tool. The current balance is first compounded forward at the annual return divided by 12, becoming P(1+r)^n by the deadline. That future value is subtracted from the goal, and the annuity formula is solved for the payment that builds the remainder: PMT = (FV − P(1+r)^n) · r / ((1+r)^n − 1). If current savings alone would exceed the goal, the required deposit is zero. Deposits are assumed to land at the end of each month and the rate is held constant — real returns will wander around whatever average you enter.
References: Bankrate methodology.
Last reviewed July 2, 2026 · Editorial policy