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Investing & Retirement
Savings Goal Calculator — Monthly Contribution & Time to Reach Your Target
Plan the down payment, emergency fund, vacation or any target with compound growth built in
Almost every money goal in American life comes down to two questions: how much do I put away each month, and when will I get there? Whether you're building a 6-month emergency fund, saving a 20% down payment on a house, or stashing cash for a wedding or a new truck, the math is the same — and a regular savings or money-market account quietly helps by paying interest while you save.
This calculator answers either question. In "monthly contribution" mode you enter your target, what you've already saved, the expected annual return, and how many years you have — and it solves for the deposit you need each month. In "time to goal" mode you enter a monthly deposit instead, and it tells you how many months and years until you hit the number.
The engine combines two standard formulas. First, your current savings grow on their own: FV = PV × (1 + r)^n, where r is the monthly rate (annual ÷ 12) and n is the number of months. Second, your monthly deposits grow as an annuity: FV = PMT × [((1 + r)^n − 1) ÷ r]. Add them and you have your projected balance.
To find the required monthly deposit, we rearrange: PMT = (Goal − PV × (1 + r)^n) ÷ [((1 + r)^n − 1) ÷ r].
Worked example. Goal $50,000, already saved $10,000, expected return 6% a year (0.5% a month), time frame 5 years (60 months). Your $10,000 grows to 10,000 × (1.005)^60 = $13,488.50. That leaves $36,511.50 to come from deposits. The annuity factor is ((1.005)^60 − 1) ÷ 0.005 = 69.77. So PMT = 36,511.50 ÷ 69.77 ≈ $523 a month. Over 60 months you'd contribute about $31,399 out of pocket, and roughly $8,601 of the $50,000 goal comes from interest (your starting balance plus the deposits compounding).
The common mistake: people divide the goal by the number of months and stop there — $50,000 ÷ 60 = $833 — ignoring both the head start their current balance gives them and the interest compounding along the way. That overshoots the deposit you actually need. The other trap is using the annual rate as if it were monthly; always divide the yearly return by 12 first.
Results here are estimates. Real returns vary year to year, and a guaranteed-rate savings account behaves differently from a market-based investment. Use this to set a realistic target deposit, then revisit it as your rate or timeline changes.
📖 See also: How Much Should You Have Saved by Each Age?
Calculator
Fill in the fields and click "Calculate" for instant results.
📰 Formula
• Monthly rate: r = annual return / 12 / 100 • Future value of current savings: FV = PV × (1 + r)^n • Future value of deposits: FV = PMT × [((1 + r)^n − 1) / r] • Required deposit: PMT = (Goal − PV × (1 + r)^n) / [((1 + r)^n − 1) / r] • Months to goal: n = ln[(Goal × r + PMT) / (PV × r + PMT)] / ln(1 + r)
📰 Formula
• Monthly rate: r = annual return / 12 / 100 • Future value of current savings: FV = PV × (1 + r)^n • Future value of deposits: FV = PMT × [((1 + r)^n − 1) / r] • Required deposit: PMT = (Goal − PV × (1 + r)^n) / [((1 + r)^n − 1) / r] • Months to goal: n = ln[(Goal × r + PMT) / (PV × r + PMT)] / ln(1 + r)
🧪 Worked examples
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Example 2
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Example 3
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Example 4
⚠️ Common mistakes
- Dividing the goal by the number of months and ignoring interest and your starting balance.
- Plugging the annual return in as the monthly rate instead of dividing by 12.
- Forgetting to subtract current savings, so the deposit comes out too high.
- Setting an expected return far above what a savings account actually pays.
💡 Tips
- Always divide the annual return by 12 to get the monthly rate before compounding.
- Your current balance keeps growing on its own — count it before sizing the new deposit.
- For a guaranteed plan use a conservative rate (an FDIC-insured account), not a stock-market average.
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❓ Frequently asked questions
How much do I need to save each month to reach my goal?
Subtract the future value of your current savings from the goal, then divide by the annuity factor ((1 + r)^n − 1) ÷ r. For a $50,000 goal in 5 years at 6% with $10,000 saved, that's about $523 a month.
How is interest factored into a savings goal?
Two ways: your existing balance grows by (1 + r)^n, and each monthly deposit earns interest from the day it lands. Both reduce how much you have to contribute out of pocket.
What interest rate should I use for a savings goal?
For a near-term, guaranteed plan, use what a high-yield savings account or CD actually pays. For a long-term investing goal, a 5–7% annual estimate is more typical — but it's not guaranteed, so treat the result as an estimate.
Why is my required deposit lower than the goal divided by months?
Because interest does part of the work. Simply dividing the goal by the number of months ignores compounding and your head start, so it overstates the deposit you actually need.
How do I calculate how long it takes to reach a savings goal?
Use the time formula: n = ln[(Goal × r + PMT) ÷ (PV × r + PMT)] ÷ ln(1 + r), where r is the monthly rate. The calculator's 'time to goal' mode does this for you and converts months to years.
Does it matter if I deposit at the start or end of the month?
Slightly. This calculator assumes deposits at the end of each month (an ordinary annuity). Depositing at the start earns one extra month of interest each time, so you'd reach the goal a touch faster.
Should I count my 401(k) or only a savings account?
Use whichever account funds the goal. For a house down payment that's usually a savings or brokerage account with its own rate — don't mix in retirement money you can't easily access.
What if my expected return is 0%?
Then it's straight division: required deposit = (goal − current savings) ÷ number of months. The calculator handles a 0% rate without breaking.
Is the result guaranteed?
No. It's an estimate. Actual returns vary, rates change, and inflation erodes buying power over long horizons. Revisit your plan whenever your rate, balance or timeline shifts.