Run 3 return-rate scenarios to see a realistic range of outcomes — then adjust your monthly amount until it fits your budget.
Open the Money Growth Calculator| Return rate | Final balance | Total contributed |
|---|---|---|
| 5% (conservative) | ~$83,000 | $36,000 |
| 7% (mid) | ~$122,000 | $36,000 |
| 10% (optimistic) | ~$226,000 | $36,000 |
Investing $100 a month for 30 years means contributing just $36,000 of your own money — yet at a 7% return, compounding adds an extraordinary $86,000 on top, growing your balance to around $122,000. Thirty years transforms a tiny monthly habit into a six-figure sum, with compounding adding more than twice what you contributed yourself. This is one of the most compelling examples of why starting early matters — $100 a month from age 30 could mean $122,000 by retirement at 60 with almost no effort.
If $100/month feels hard right now, test a smaller starting amount and increase it each year. Even small step-ups can move the result a lot over long horizons.
It can be. The biggest drivers are consistency and time. Use the calculator to compare multiple return scenarios.
Try 5% (conservative), 7% (mid), and 10% (optimistic) to see a range.
No. Treat results as estimates. You can lower your assumed return rate to be conservative.
If you can’t do both, extra time often helps a lot. Then increase contributions over time.
See /how-compound-interest-works.html.