How it's calculated
With N months, monthly growth g = (1 + APY)1/12 and i = g − 1:
Goal in future dollars: FV = Goal · (1 + inflation)^(N/12)
Monthly deposit needed:
PMT = [FV − Current·(1+i)^N] · i / [(1+i)^N − 1] (end of month)
PMT = the above / (1 + i) (start of month)
PMT = (FV − Current) / N (no interest)
If your current savings alone grow past the goal, PMT = 0.
The deposit shown is PMT rounded UP to the next cent.
- The rate is an effective annual rate (APY): twelve monthly steps add exactly the APY. This matches how US banks quote savings accounts.
- Rounded up to the cent. You can't deposit a fraction of a cent, so the monthly amount is rounded up: depositing the amount shown always reaches the goal. Every total, the chart and the table use that rounded deposit, so they add up exactly, and you usually finish a few cents above the goal. Our tests check this for many scenarios.
- The rate is constant, with no taxes or fees.
- The weekly figure is the same yearly total spread over 52 weeks, an approximation rather than an exact weekly schedule.
Worked examples
1. $50,000 in 5 years with $5,000 saved at 4% APY
i = 1.041/12 − 1 = 0.0032737398 (about 0.3274% a month), N = 60 and (1 + i)60 = 1.045 = 1.2166529024. Your $5,000 grows to $6,083.26, leaving $43,916.74 to fund. PMT = 43,916.74 × 0.0032737398 ÷ (1.2166529024 − 1) = $663.6051, rounded up to $663.61 a month. Depositing that 60 times totals $39,816.60; with your $5,000 and $5,183.73 of interest you finish with $50,000.33, $0.33 over the goal because of the rounding. Load this example
2. $10,000 in 2 years, with and without interest
With no interest: 10,000 ÷ 24 = $416.6667, rounded up to $416.67 a month (24 deposits total $10,000.08). At 4.5% APY: $399.33 a month ($399.3273 rounded up). You deposit $9,583.92 and interest adds $416.15, ending at $10,000.07. Load this example
3. A $30,000 down payment in today's dollars
With 3% inflation, $30,000 of today's buying power is $32,781.81 in 3 years. Starting with $2,000 at 4% APY, you need $800.51 a month ($800.5037 rounded up). Load this example
Frequently asked questions
How much do I need to save each month to reach my goal?
Without interest, divide what you still need by the number of months. With interest, the formula above gives a slightly lower amount because interest does part of the work. The calculator does both instantly.
How much do I need to save a month to get $10,000?
In one year with no interest: $833.34 a month ($10,000 ÷ 12 = $833.333…, rounded up to the cent so 12 deposits reach the goal). In two years: $416.67 a month. With a 4.5% APY over two years, about $400 a month ($399.33). Enter your own deadline above.
Does this savings calculator include interest?
Yes, if you enter a rate. Use your account's APY. Set it to 0 for a savings calculator with no interest.
Should I deposit at the start or end of the month?
Depositing at the start gives each deposit one more month of interest, so the required amount is slightly lower. The difference is small at savings-account rates.
How do I plan for inflation?
Enter an inflation rate and the goal is treated as today's dollars, growing each year so it keeps its buying power. Useful for goals several years away, like a house or college.
Spotted an error?
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