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) | ~$250,000 | $108,000 |
| 7% (mid) | ~$366,000 | $108,000 |
| 10% (optimistic) | ~$678,000 | $108,000 |
Investing $300 a month for 30 years means contributing $108,000 of your own money — yet at a 7% return, compounding adds a remarkable $258,000 on top, growing your balance to around $366,000. Thirty years transforms $300 a month into a third of a million dollars, with compounding adding more than twice what you contributed yourself. At 10% returns you're approaching $700,000 — a genuinely life-changing outcome from a habit that costs less than many Australians spend on subscriptions and eating out each month.
For Australians, $300 a month over 30 years is one of the most powerful "slow and steady" wealth-building strategies available. Directed into a low-cost ETF like VAS or VGS, and assuming a 7% average annual return broadly in line with long-run ASX and global index performance, your $108,000 in contributions grows to around $366,000 — with compounding adding more than twice what you contributed. Someone starting this habit at 35 could reach retirement age with a third of a million dollars built entirely outside of super from a modest monthly commitment. Tools like Sharesight make it easy to track your actual portfolio returns against these projections over the long haul.
Thirty years is where $300 a month becomes genuinely life-changing. Here's the comparison across time horizons at a 7% return:
| Time period | Total contributed | Final balance (7%) | Growth from compounding |
|---|---|---|---|
| 10 years | $36,000 | ~$52,000 | ~$16,000 |
| 20 years | $72,000 | ~$156,000 | ~$84,000 |
| 30 years | $108,000 | ~$366,000 | ~$258,000 |
Contributions triple from 10 to 30 years, but compounding growth jumps from $16,000 to $258,000 — more than 16 times. Starting early and staying consistent is what makes the difference.
If $300/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.