What-If · projection
What happens if I invest $100 a month for 30 years?
The point of this one is that the amount is small. $100 a month is a modest, common starting figure — this projects what consistency at that level compounds to over 30 years, in today's dollars beside the nominal figure.
At a 5% nominal return and 2.5% inflation, $100 a month for 30 years grows to about $40k in today's dollars — $83k nominal — on $36k contributed. These are illustrative assumptions, not a prediction or recommendation.
Year by year (default assumptions)
| Year | Today's dollars | Nominal |
|---|---|---|
| 1 | $1,198 | $1,228 |
| 5 | $6,011 | $6,801 |
| 9 | $10,893 | $13,604 |
| 13 | $15,895 | $21,911 |
| 17 | $21,065 | $32,052 |
| 21 | $26,456 | $44,434 |
| 25 | $32,121 | $59,551 |
| 29 | $38,119 | $78,007 |
| 30 | $39,677 | $83,226 |
Assumptions & method
5% nominal annual return, 2.5% inflation (≈2.4% real). Conservative, illustrative, and editable — not a forecast.
Full defaults, sources, and the engine logic are on the methodology page.
Reviewed by Sam, Richify's What-If Strategist · Last reviewed 2026-07-01
Frequently asked questions
- Is $100 a month even worth it?
- The projection lets you judge that directly: it shows what that contribution compounds to and how much of the result is your own money versus growth. It's a calculation, not a recommendation about whether to do it.
- How much of the result is just my contributions?
- Over 30 years at $100/month you contribute $36,000. The figure above shows the projected total, so the gap between the two is the modelled compounding — an assumption, not a certainty.
- Does starting amount or time matter more?
- With compounding, time generally does more work than the amount, because early contributions compound longest. Raise the years and watch how the result moves relative to raising the monthly amount.
- What return and inflation does this use?
- 5% nominal and 2.5% inflation by default — conservative, illustrative figures on the methodology page. Editable; the projection recomputes from whatever you set.
Try your own numbers with Sam
Sam explains the math of any scenario you set — no advice, just the projection.
Educational projection only — not financial advice, a forecast, or a recommendation. Results are the arithmetic of the assumptions you set; real returns vary. Figures shown in both today's dollars and nominal terms.
