Compute the monthly contribution needed to reach any savings goal by a specific date.
Required monthly contribution
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Total contributed
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Growth from interest
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Worked example
Suppose you want $50,000 in 5 years for a house down payment, you already have $5,000 set aside, and your savings earn 5% a year. First the tool grows your existing $5,000 forward. Compounding monthly at 5% for 60 months, that balance becomes about $6,417 by the goal date on its own. That means you only need your monthly deposits to supply the remaining $43,583. Solving the savings annuity for that gap gives a required contribution of about $640.87 a month. Over the 5 years your deposits plus the original $5,000 add up to about $43,452 of your own money, and the interest earned along the way contributes roughly $6,548 toward the goal. If your starting balance were larger or your rate higher, the future value of what you already have would cover more of the target, and the required monthly amount would fall.
| Item | Amount |
|---|---|
| Goal | $50,000 |
| Current balance grown to goal date | $6,417 |
| Gap to fund with deposits | $43,583 |
| Required monthly contribution | $640.87 |
| Total contributed (incl. $5,000 start) | $43,452 |
| Growth from interest | $6,548 |
How it is calculated
The tool works backward from the target. It first compounds your current balance forward to the goal date using the monthly rate, which is the annual rate divided by 12, over the number of months in your horizon. Subtracting that future balance from the target gives the amount your new deposits must cover. It then inverts the future-value-of-an-annuity formula to find the level monthly contribution that grows to exactly that remaining amount by the deadline. Total contributed adds every deposit to your starting balance, and the growth figure is the target minus what you put in, which is the interest your savings earned along the way. If your existing balance already grows past the target on its own, the required contribution is zero and the tool says so. The result is a planning estimate that assumes a steady return and ignores tax on interest, so a tax-advantaged or high-yield account changes the picture.