Time-to-Million Calculator

Time to reach $1,000,000 with monthly contributions and compound growth

This Time-to-Million Calculator estimates how long it may take for your investments to reach a target amount, typically $1,000,000. It combines three drivers of growth that most people actually control: your current starting balance, your ongoing monthly contribution, and the rate of return you expect over time. Instead of giving you a single raw number, it also shows what portion of the ending value comes from your own contributions versus investment growth.

The default target is one million dollars, but the target field lets you use the same tool for any milestone, like $250,000, $500,000, or $2,000,000. This matters because the early part of the journey is often dominated by contributions, while later years are dominated by compounding. Changing the target helps you see that shift. The calculator also supports two realistic upgrades that remain optional: contribution growth (if you increase contributions over time) and inflation (to estimate what “a million in today’s money” might mean in the future).

To use it, enter your current balance, how much you add each month, and your expected annual return. If you are not sure about the return, choose a conservative number and rerun a couple scenarios. If you expect your contributions to increase as your income rises, add a contribution growth rate. If you want a more honest yardstick, enter an inflation rate so the calculator can estimate how long it takes to reach your target in real terms, meaning the target grows over time to maintain purchasing power.

Assumptions and how to use this calculator

• Contributions are assumed to be made monthly, and the portfolio is modeled with monthly compounding.
• Return is an average annual rate. Real markets vary month to month, so your real path will be uneven.
• Contribution growth (if used) is applied once per year to your monthly contribution amount.
• Inflation adjustment (if used) treats your target as “in today’s money,” so the nominal target increases over time.
• The model ignores taxes, fees, and withdrawals. If those apply to you, use a lower return assumption as a rough offset.

Common questions

Is this prediction guaranteed?

No. It is a deterministic projection based on the inputs you provide. The value is in comparing scenarios and understanding what needs to change (contribution, time, return, or target) to reach your goal.

What if my monthly contribution is zero?

The calculator can still work if your starting balance is positive and your return is greater than 0%. If both contributions and returns are zero (or negative), the target cannot be reached and the calculator will tell you that.

Should I use nominal or inflation-adjusted results?

If your goal is a specific number in an account statement, nominal is fine. If your goal is lifestyle purchasing power, inflation-adjusted is the more realistic benchmark because it accounts for rising costs over time.

What return should I enter if I do not know?

Use a conservative long-term estimate and test a range. Many people run three cases: cautious, middle, and optimistic. The point is to see sensitivity: small changes in return can meaningfully change timelines.

How can I make the timeline shorter without taking extreme risk?

In most realistic cases, increasing contributions and sticking to them matters more than chasing a higher return. Contribution growth, even a few percent per year, can noticeably improve outcomes if sustained.