A lump sum gets more time in the market, but results still depend on your return assumptions. Compare conservative, mid, and optimistic scenarios.
Open the Money Growth Calculator| Return rate | Final balance | Amount invested |
|---|---|---|
| 5% (conservative) | ~$265,300 | $100,000 |
| 7% (mid) | ~$387,000 | $100,000 |
| 10% (optimistic) | ~$672,700 | $100,000 |
Investing $100,000 as a one-off lump sum for 20 years is one of the most powerful wealth building scenarios available to Australians with access to a significant lump sum. At a 7% return your $100,000 nearly quadruples to around $387,000 — with compounding adding an extraordinary $287,000 on top. At 10% the result is remarkable — $672,700, nearly seven times your original investment from a single deposit with no further contributions. For Australians in their 40s or early 50s who invest a $100,000 lump sum and leave it untouched, this could form the cornerstone of a genuinely comfortable retirement.
If you have the money ready now, investing earlier gives compounding more time. Waiting in cash can reduce long‑term growth (but may reduce short‑term risk).
If investing everything at once feels risky, model a smaller lump sum plus monthly contributions. You’ll see the tradeoff between time invested and timing risk.
Often lump sum wins mathematically because money is invested sooner, but behaviour and timing risk matter.
Try 5% (conservative), 7% (mid), 10% (optimistic) to see a range.
No. Treat results as estimates. You can lower the assumed return rate to be conservative.
If the timeline is short, a stable savings option may be safer. Consider using the ETF vs Savings comparison.
See /how-compound-interest-works.html.