How a future target becomes a required monthly deposit
A savings goal starts with the amount you want at a future date and solves for the equal deposit needed at each month-end. The calculator credits projected growth of money already saved before finding the remaining gap.
A savings target reverses the usual future-value calculation. The current balance is projected forward first; the remaining future-value gap is assigned to equal month-end deposits. This makes the required contribution responsive to both time and any growth assumption.
The tool solves the deposit amount backward from a specified target and projects current savings first. Its goal breakdown shows when existing money already covers the target under the chosen assumption.
How target, current savings, assumed rate and years set the deposit
The calculation works backward from the target. Current savings are grown first, and only the remaining gap is spread across equal month-end deposits.
- Target future balance
- The amount you want on the target date, treated as a fixed future sum. The requirement rises in step with the unfunded gap: with 1,000 saved and 0% growth over 2 years, a 5,000 target needs 166.67 a month. A goal priced in today's money will fall short unless it is raised for inflation before entry.
- Saved already
- Money already set aside, grown at the assumed rate before the gap is measured. In the 0% example it lowers the requirement from 208.33 to 166.67 a month. If current savings would pass the target on their own, the answer is zero rather than negative; 4,600 at 5% reaches 5,082.73 in 2 years.
- Assumed annual rate
- A fixed nominal rate applied monthly to current savings and new deposits alike. Raising it from 0% to 5% in the example lowers the deposit from 166.67 to 154.65, because 1,000 grows to 1,104.94 and the deposits earn too. Over short horizons the rate matters little; use 0% for money kept in cash.
- Time until target
- Whole years, converted into monthly deposits. One more year makes a large difference: the 0% example falls from 166.67 a month over 2 years to 111.11 over 3. Count only the time in which you will actually deposit, since the formula assumes no skipped months.
Steps
- Enter a positive future target and any amount already saved.
- Choose an assumed fixed annual rate and a whole number of years.
- Read the required monthly amount and the future-value gap that the deposits must cover.
Reading tip: Use 0% as a conservative no-growth comparison, then try a plausible rate separately. If the existing balance alone is projected above the goal, the required new deposit is zero.
Goal-setting questions a backward savings calculation answers
Set a monthly target
Solve the equal month-end amount needed for a specified future balance.
Credit money already saved
Project existing savings before calculating the remaining future-value gap.
Compare time horizons
See how one more year changes the required monthly amount under the same assumption.
Check a zero-growth plan
Use a 0% rate to understand the pure deposit amount with no assumed earnings.
How the calculation works
- target
- Positive balance the user wants at the end of the horizon.
- P
- Current savings balance projected forward before adding new monthly deposits.
- i / N
- Monthly fixed decimal rate / number of end-of-month contribution opportunities.
- G / C
- Future-value shortfall after current savings grow / required equal monthly contribution.
The monthly contribution is solved before display rounding. If current projected savings already cover the target, C is zero.
What every part means
- target
- Positive balance the user wants at the end of the horizon.
- P
- Current savings balance projected forward before adding new monthly deposits.
- i / N
- Monthly fixed decimal rate / number of end-of-month contribution opportunities.
- G / C
- Future-value shortfall after current savings grow / required equal monthly contribution.
Calculate it step by step
Grow the money already saved at the assumed monthly rate.
No deposit is required when current savings cover the target under the assumptions.
Solve the ordinary-annuity future-value formula for an end-of-month deposit; at 0%, use G/N.
The engine recomputes the projected final balance using the solved contribution. Display rounding may make the printed monthly amount appear to miss the target slightly.
See how Calculation Guide tests examples and handles calculation limits.
See it in practice
- Target future balance
- 5000 currency units
- Saved already
- 1000 currency units
- Assumed annual rate
- 0 %
- Time until target
- 2 whole years
Target 5,000, current 1,000, rate 0%, N = 24: current savings stay 1,000; gap G = 4,000; C = 4,000/24 ≈ 166.67 each month before display rounding.
- Current balance at target date1,000
- Remaining future-value gap4,000
Interpretation & limitations
How to read your result
The headline is a monthly amount to set aside, not an amount you already have. Check the future-value gap and total new deposits to see how much of the goal depends on new saving.
Where this estimate stops
The calculation assumes a constant nonnegative nominal rate, equal deposits and no withdrawals. A goal with tax or inflation requirements needs those requirements reflected in the target itself.
Frequently asked questions
01What if existing savings already meet the target?
The monthly requirement is zero if the current balance is projected to reach or exceed the target under the entered rate.
02Why is this different from the Investment Calculator?
Savings solves for the monthly deposit required to reach a target; Investment projects the target reached from a deposit you choose.
03What happens at 0% interest?
The unfunded target gap is divided evenly by the number of months.
04Can the monthly amount be negative?
No. If projected current savings already cover the target, the required amount is zero.
05Are deposits at the beginning of each month?
No. They occur after each month's interest, so changing the timing would change the requirement.
06Is the final balance guaranteed?
No. It depends on the entered fixed rate and regular deposits being achieved.
07My goal is in today's money. How do I allow for inflation?
Raise the target by your assumed inflation rate before entering it: target × (1 + inflation)^years. A 20,000 goal at an assumed 5% inflation over 5 years becomes 25,525.63. With 2,000 already saved and a 6% assumed rate, the monthly deposit then rises from 247.99 to 327.19.