This calculator uses compound interest formulas to project the growth of your current savings plus regular monthly contributions at a constant annual return. It then finds (via binary search) the number of months needed to reach your target amount, accounting for monthly compounding. The timeline table shows your balance at the end of each year until you hit the goal.

We assume a fixed annual rate of return (compounded monthly), consistent monthly contributions at the end of each month, and no taxes or fees. Real-world returns fluctuate; this is a planning estimate, not a guarantee.

The calculator determines the month when your balance first equals or exceeds the target amount. Because contributions and compounding happen monthly, the final balance may modestly overshoot your exact target.

No, the tool uses nominal returns. To account for inflation, you could either increase your target amount to reflect future purchasing power or reduce your expected return by the inflation rate (e.g., 7% nominal return with 2% inflation ≈ 5% real return).

If your monthly contribution is too low or the return is too low relative to the target, it may take an extremely long time (or be mathematically impossible if you have no growth and your contributions alone never reach the target). The tool will show more than 100 years if needed, but you'll likely want to adjust your inputs (increase savings or return, lower target).

Absolutely. Many users set a retirement savings target and use the timeline to see if their current savings rate is sufficient. Just enter your desired retirement nest egg as the target, and your current age to see at what age you might achieve it.

We calculate contributions at the end of each month, which is the most common convention. This slightly delays growth compared to beginning-of-month contributions; the real-world difference is minimal for long timelines.