Find the monthly deposit for a target
Use this planner when you know current savings, a target balance, a timeline in months or years, and a nonnegative nominal annual rate. It solves for a fixed deposit made at the end of each month. Keep target and current savings in one currency and choose the time unit deliberately.
Product-defined target method
The timeline becomes a number of months and the monthly rate is annual rate / 12. Current savings grow for that full period. If they already reach the target, required monthly savings are zero. Otherwise, the remaining future-value gap is divided by the end-of-month annuity factor. At 0%, the gap is divided evenly by the number of months.
With $1,000 saved, a $10,000 target, 12 months, and 2.5% annual interest, required monthly savings are $739.36. The displayed plan has $9,872.34 in contributions and $127.66 in interest, ending at $10,000. At 0%, the monthly requirement is exactly $750. As a timeline comparison, entering 12 years instead of 12 months lowers the modeled deposit to $51.57, but commits the plan for 144 months.
Planning checks
Confirm the unit first, then rerun a shorter timeline and a zero-rate case. A plan that only works under the most favorable rate assumption has little margin for missed deposits.
Current savings, target, and rate cannot be negative. The timeline must be greater than zero in every case. If current savings already exceed the target, the projected balance can exceed the target and no withdrawal is assumed. Blank, unknown-unit, and invalid numeric values are rejected.
The model assumes a fixed rate and deposits at month-end; it excludes fees, taxes, inflation, changing deposits, withdrawals, and account restrictions. It is not investment advice or a guarantee. Use the savings calculator to project a known deposit amount.