How the monthly deposit is found
The goal is the future value of two things: the money you already have, growing at the interest rate, and a series of equal monthly deposits, each growing from the month it is made. The calculator solves the standard future-value-of-an-annuity formula for the deposit. At 0% interest it is simply the shortfall divided by the number of months.
Worked example (pre-filled). To reach $10,000 in 24 months starting with $1,500 at 4% (compounded monthly), the current savings grow to $1,624.71, and the rest needs $335.78 a month (about $77.49 a week). Total deposits are $8,058.72 and interest contributes $441.28.
The result is the deposit at a constant rate with no withdrawals; a rate change or a missed month changes it. Taxes on interest are not included. Framed per paycheck, $335.78 a month is close to half that every biweekly payday; the paycheck calculator shows what take-home pay is left after withholding to save from. This page computes; it does not recommend a loan, lender, investment or tax position.
Formula and assumptions
deposit = (goal − current × (1 + i)N) × i ÷ ((1 + i)N − 1)
i = 0: deposit = (goal − current) ÷ N
- Deposits at the end of each month; interest compounds monthly.
- If current savings alone would exceed the goal, the deposit is zero.
Frequently asked questions
How much do I need to save a month to reach $10,000 in 2 years?
With nothing saved and no interest, $416.67. Starting with $1,500 at 4% it is $335.78 a month.
Does interest make much difference over two years?
A little. On this example, interest covers about $441 of the $10,000; over longer periods and higher rates it covers far more.
How do I save a set amount per paycheck?
Divide the monthly deposit by the number of paychecks a month: 2 for semi-monthly, 26 ÷ 12 = 2.17 for biweekly.
What if I can save more some months?
The calculator assumes a level deposit. Extra deposits reduce what is needed later; re-run it from the new balance and remaining months.
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Sources
This calculator gives general estimates from the figures you enter. It is not tax, legal, payroll or financial advice. See our disclaimer.