Savings Goal Calculator

Three savings-goal solvers in your browser. Time-to-goal tells you how long it takes to reach a target at a fixed monthly contribution. Contribution-to-goal solves the inverse: what monthly contribution you need to hit a target by a deadline. Schedule preview walks the balance year by year. All math runs locally — nothing is uploaded, nothing is tracked.

Time to reach goal
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Final balance
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Total contributions
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Total interest earned
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Surplus over goal
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How it works

All three modes are closed-form solutions to the future-value formula FV = PV · (1+r)n + PMT · [((1+r)n − 1) / r], where r is the monthly rate (annualRatePercent / 12 / 100), n is the number of months, PV is your current savings, and PMT is the per-month contribution. With start-of-month contributions the contribution term is multiplied by (1+r) to put each deposit one period earlier.

Time-to-goal solves the log-form (1+r)n = (FV·r + PMT) / (PV·r + PMT) and rounds n up to the next whole month — a fractional month still counts as one on a calendar. Contribution-to-goal rearranges the same equation to PMT = (FV − PV·(1+r)n)·r / ((1+r)n − 1) and rounds the answer up to the next cent so the goal is always met. The schedule builds the per-row balance by chaining closed-form future-value evaluations starting from the previous row's end balance.

Educational only — not financial advice. Real savings accounts have variable rates, fees, tax treatment, and deposit-timing nuances this tool does not model.