Watch a lump sum plus monthly contributions compound over time, with a year-by-year breakdown of contributions versus growth.
A projection based on the return you enter, not a guarantee.
Future value here is your initial investment compounded at your chosen rate and frequency, plus the future value of your ongoing monthly contributions. The share of your final balance that comes from growth rather than contributions rises the longer the money sits, which is the entire case for starting early over trying to invest a larger amount later.
The 7% figure in the return field is not a house prediction. It is a commonly cited long-run average for a diversified, stock-heavy portfolio after adjusting for inflation, drawn from decades of historical U.S. market data. Actual results in any given decade can land well above or below that figure, sometimes for years at a stretch, so treat it as a stress-test assumption rather than an expected outcome.
General background on how compounding and markets work: Investor.gov compound interest calculator and how stock markets work, both from the U.S. Securities and Exchange Commission's investor education site.
| Year | Contributed to date | Projected balance |
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Comparing this against a workplace plan? The 401k calculator runs the same style of projection with an employer match layered in, and the retirement calculator checks the result against a spending goal instead of showing raw growth.
No. The retirement calculator compares a projected balance against a spending target and tells you if you are on track. This tool is a pure growth projection, useful for testing a taxable brokerage account, a 529, or any pot of money you want to watch compound on its own, separate from a retirement goal.
Both approaches work over long horizons. Investing a lump sum immediately has historically outperformed spreading it out, on average, simply because more money is in the market for longer. Spreading contributions out monthly, often called dollar-cost averaging, mainly helps with the psychology of not trying to time a single entry point, not with raising expected returns.
Only a little. Moving from annual to monthly compounding on the same nominal rate raises the effective return, but the difference is small compared to the effect of raising the rate itself, extending the time horizon, or increasing contributions. Pick the frequency that matches how your account actually compounds and do not spend much time optimizing it further.
In the early years, most of your balance is still your own contributions, so growth in dollar terms looks modest even at a healthy percentage return. Later years show larger dollar gains because a bigger base is compounding, not because the return rate changed. This is the same math, just applied to a bigger number each year.
No. Every number here is a projection based on the rate you enter, not a forecast or a promise. Real markets fluctuate year to year, and a sequence of poor early returns can leave you well short of a smooth-average projection even if the long-run average eventually matches your assumption.