Savings Goal Calculator
Work out the monthly deposit needed to hit a savings goal, or how long your current plan will take.
- Monthly deposit needed
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- Total you deposit
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- Interest earned
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- Final balance
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- Goal reached by
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Year-by-year plan
| Month | Deposited | Interest | Balance |
|---|
Estimates only. Real savings are affected by tax, fees, inflation and a return rate that changes from year to year — this is a planning aid, not financial advice.
How it works
Tell the calculator what you are saving for, what you have already put aside and what annual
return you expect, and it fills in the missing piece. In “How much to save each
month” mode it solves the standard future-value-of-an-ordinary-annuity formula
FV = P(1+i)ⁿ + PMT·((1+i)ⁿ − 1)/i for the payment, giving
PMT = (FV − P(1+i)ⁿ)·i / ((1+i)ⁿ − 1). In “How long it will
take” mode it solves the same equation for the number of periods,
n = ln((FV·i + PMT) / (P·i + PMT)) / ln(1+i), and rounds up to a whole month.
Interest compounds monthly at i = annual rate ÷ 12 and deposits land at the end
of each month (an ordinary annuity, the convention banks use for standing orders). With a 0%
return both formulas collapse to plain division, so the numbers stay sensible for a cash
savings jar too.
The year-by-year table shows how the balance builds and when compounding starts to do real work, and you can export it as CSV for a spreadsheet or copy a plain-text summary. Everything is computed in your browser with plain JavaScript — no account, no ads, and none of your figures ever leave the device.
Frequently asked questions
How much do I need to save each month to reach my goal?
Enter your goal, what you have already put aside, the annual return you expect and how many months you have. The calculator solves the future-value-of-an-ordinary-annuity formula FV = P(1+i)ⁿ + PMT·((1+i)ⁿ − 1)/i for the payment, giving PMT = (FV − P(1+i)ⁿ)·i / ((1+i)ⁿ − 1), where i is the annual rate divided by 12. Saving 10,000 from scratch in 24 months with no interest needs 416.67 a month; at 6% a year it needs less, because compounding covers part of the gap.
How long will it take to reach my savings goal?
Switch to "How long it will take" and enter your monthly deposit instead of a deadline. The same equation is solved for the number of periods: n = ln((FV·i + PMT) / (P·i + PMT)) / ln(1+i), rounded up to a whole month. Saving 200 a month towards 10,000 with 1,000 already banked at 6% a year takes 40 months. If the deposit and rate can never close the gap, the tool says so instead of showing a nonsense number.
Does the calculator include interest, and how is it compounded?
Yes. Interest compounds monthly at i = annual rate ÷ 12, and deposits land at the end of each month, which is an ordinary annuity and how banks credit a standing order. Set the rate to 0% for a plain cash jar and both formulas collapse to simple division. Results ignore tax, fees and inflation, so treat them as a planning estimate rather than a guarantee. Everything is computed in your browser; your figures are never uploaded.