Turn a future target into a monthly savings plan
Instead of asking how much an existing monthly deposit might grow, this calculator works backward from a target. It estimates the future value of the money you already have, subtracts that projected amount from the goal, and then calculates the recurring monthly deposit needed to close the gap.
Formula
PMT = (FV − PV × (1 + r)^n) × r ÷ ((1 + r)^n − 1)FV is your target balance, PV is the current balance, r is the monthly interest rate, and n is the number of monthly deposits. At a zero rate, the remaining target is divided evenly across the remaining months.
Why the target date matters
A longer horizon gives both the current balance and future deposits more time to grow. A shorter horizon requires larger monthly contributions because there are fewer deposits and less time for compounding.
Worked example
Suppose you have $5,000 today and want $25,000 three years from now. At an assumed 4% annual rate, the calculator estimates the monthly end-of-month contribution required to reach the goal. Try changing the target date by a year to see how strongly time affects the monthly requirement.
Assumptions and limitations
The model assumes a constant annual rate converted to a monthly rate, equal end-of-month deposits, no withdrawals, and no taxes or fees. It is a planning model rather than a guarantee of future returns.
Frequently asked questions
How does the calculator determine the monthly savings amount?
It grows the current balance at the selected monthly rate, then solves the future-value annuity formula for the monthly contribution needed to cover the remaining target.
What happens if my current savings can already reach the goal?
If the projected future value of your current balance already meets or exceeds the target, the required monthly contribution is shown as zero.
Are deposits assumed at the beginning or end of each month?
This calculator assumes each recurring contribution is deposited at the end of the month.
Can actual investment returns differ from the estimate?
Yes. The calculator assumes a constant rate. Real savings or investment returns can change, and fees or taxes may reduce growth.
Why is the target date converted to months?
Recurring contributions are modeled monthly, so the selected future date is converted into the number of monthly contribution periods remaining.