Use conservative, mid, and optimistic return assumptions to see a realistic range of outcomes — then decide what’s feasible for your budget.
Open the Money Growth Calculator| Return rate | Final balance | Total contributed |
|---|---|---|
| 5% (conservative) | ~$178,000 | $104,000 |
| 7% (mid) | ~$226,000 | $104,000 |
| 10% (optimistic) | ~$329,000 | $104,000 |
Investing $100 a week for 20 years means contributing $104,000 of your own money — and at a 7% return, compounding adds an impressive $122,000 on top, growing your balance to around $226,000. That's more than double your contributions, with compounding matching almost everything you put in. For many Australians, $100 a week is a realistic target that with discipline over 20 years can quietly build a quarter of a million dollars.
If you invest $100/week for 20 years, the result depends heavily on the return rate. Use the calculator to test a conservative, mid, and optimistic scenario.
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It’s a solid starting habit. The best amount is one you can maintain consistently, then increase over time.
Use 5% for a conservative baseline, 7% for a mid-range estimate, and 10% as an optimistic scenario.
No. Treat results as estimates. You can lower your assumed return rate to be more conservative.
For long-term modelling, converting to monthly is usually close enough.
See the simple explanation on /how-compound-interest-works.html.