How much of the final amount comes from your own deposits?
Compounding is most useful to understand as a relationship between time, repeated contributions and an assumed return. A projection is not a prediction: it shows what would happen if the selected rate were steady.
What we put into the calculator
We start with no initial investment and contribute $200 at the end of every month for 20 years. The example assumes a constant 6% annual nominal interest rate compounded monthly. There are no fees, taxes or missed contributions.
The numbers behind the result
| Initial investment | $0 |
|---|---|
| Total monthly contributions | $48,000 |
| Total deposited | $48,000 |
| Estimated growth | $44,408 |
| Annual nominal rate | 6% |
| Years | 20 |
What the result is really telling you
The contributions are straightforward: $200 multiplied by 240 months. Any amount above that comes from hypothetical growth. Actual investments rise and fall, and a fixed average return cannot describe the path you may experience.
Try changing one number
Run the example with 4%, 6% and 8% rates. Keep the monthly amount the same. Then shorten the period to 10 years; the time horizon can matter more than a seemingly small rate change.
Open interactive calculator with this example ↗Where the estimate stops
Investment returns are not guaranteed. The calculator does not model volatility, inflation-adjusted purchasing power, tax, transaction costs or investment advisory fees. It should not be used to promise an outcome.
How this result was produced: The displayed values are evaluated by the same JavaScript formula as the linked MyFastCalcTools calculator. There are no hidden live quotes or market data in this example. The calculator explains its simplifying assumptions.