Enter your target amount, current savings, monthly contribution and expected annual interest rate to see how long it will take to reach your goal.
Saving for 20,000, starting with 3,000, adding 400 a month at 4 percent.
3 years 3 months, ending at about 20,045.61.
Over 39 months the example contributes 15,600 of deposits on top of 3,000 of starting capital — 18,600 — and interest supplies the remaining 1,446. On a short horizon the deposit is almost the entire story, which is worth knowing before spending effort chasing a slightly better rate. The balance flips on long horizons: over decades, growth eventually outweighs contributions, and that crossover is the whole argument for starting early.
The loop grows the existing balance first and then adds the new deposit, so a deposit does not earn anything in the month it arrives. This is the conservative convention and it matches how most accounts credit interest. It shifts the answer by a month at most, but it explains any small difference against a calculator that assumes deposits arrive at the start.
The loop stops the first time the balance reaches or passes the target, which is why the closing balance is slightly above the goal rather than exactly on it. In the example the final month overshoots by about 46. If you need the exact date you cross the line, it falls somewhere inside that last month.
If the date is fixed and the deposit is the unknown, adjust the monthly figure until the month count matches your deadline. That is usually the more useful direction — it converts an aspiration into a number you either can or cannot commit to, which is a decision rather than a hope. The calculator caps at 100 years and reports that the goal is unreachable rather than looping indefinitely.
Enter the target, what you have now, what you can add each month and the rate you expect. The tool steps forward month by month, applying interest and then the deposit, and reports the first month the balance reaches the goal.
For a savings account, the rate it currently pays, remembering that variable rates change. For an investment, any figure is an assumption rather than a fact, so it is worth running the calculation twice — once optimistically and once conservatively — and planning against the lower answer.
Because the calculation advances in whole months and stops at the first one that reaches the goal. The crossing happens partway through that month, so the balance shown at the end of it is a little above the target.
The calculation stops at 100 years and says so. That happens when the deposit is very small relative to the target. The fix is one of three things: a larger monthly amount, a longer horizon, or a smaller target — and seeing that explicitly is more useful than a number that implies otherwise.
One licence key, pasted into any CYZOR tool. Today it does three things: drops the CYZOR line from PDFs you send for signature, takes CYZOR branding off your forms and adds CSV export, and switches on the AI rewrite in the resume builder.