Investment Calculator

Compound Interest & Investment Calculator

See how your money grows with compound interest and regular contributions.

$10,000
7.0%
20 years
$500

$6,000/year in contributions

$302,370
After 20 years
$130,000
Total Contributed
$172,370
Investment Growth
2.3×
Growth Multiple
Contributions 43%Growth 57%

Time to Reach Milestones

$100k
Yr 10
$250k
Yr 18
$500k
Yr 26
$1M
Yr 35
$2M
Yr 45

Growth Over Time

Year-by-Year Summary

YearTotal ContributedInvestment GrowthBalance
Year 1$16,000$955$16,955
Year 2$22,000$2,413$24,413
Year 3$28,000$4,411$32,411
Year 4$34,000$6,986$40,986
Year 5$40,000$10,182$50,182
Year 6$46,000$14,042$60,042
Year 7$52,000$18,614$70,614
Year 8$58,000$23,952$81,952
Year 9$64,000$30,108$94,108
Year 10$70,000$37,144$107,144
Year 11$76,000$45,122$121,122
Year 12$82,000$54,110$136,110
Year 13$88,000$64,182$152,182
Year 14$94,000$75,416$169,416
Year 15$100,000$87,895$187,895
Year 16$106,000$101,710$207,710
Year 17$112,000$116,958$228,958
Year 18$118,000$133,742$251,742
Year 19$124,000$152,173$276,173
Year 20$130,000$172,370$302,370

Rate Comparison (after 20 years)

RateFinal BalanceGrowthMultiple
3% p.a.$182,769$52,7691.4×
5% p.a.$233,500$103,5001.8×
7% p.a.$302,370$172,3702.3×
9% p.a.$396,540$266,5403.1×
12% p.a.$608,499$478,4994.7×

The Power of Compound Interest

Compound interest is often called the “eighth wonder of the world.” Unlike simple interest, compound interest earns returns on your returns — so your money grows exponentially over time.

The key variables are time and rate. A 1% difference in return rate — say 7% vs 8% — makes a massive difference over 30 years. That's why choosing low-fee index funds (0.1% p.a.) over managed funds (1.5% p.a.) can add hundreds of thousands to your final balance.

Regular contributions are equally powerful. Adding $500/month to an investment growing at 7% for 30 years produces a balance of nearly $600,000 — even though you only contributed $180,000. The remaining $420,000 is pure compound growth.

Typical Australian Investment Returns

  • High-Interest Savings Account: 4–5% p.a. (variable, follows RBA cash rate). Low risk, instant access. Best for emergency funds and short-term goals.
  • Australian shares (ASX 200): ~9–10% p.a. average over 20+ years (including dividends). Higher short-term volatility but strong long-term returns.
  • Diversified index fund: ~7–8% p.a. average. Lower volatility than all-equities. Vanguard, BlackRock, and BetaShares offer low-fee options on the ASX.
  • Investment property: ~6–8% p.a. total return (rental yield + capital growth), varies significantly by location and leverage.
  • Superannuation (balanced): ~7–9% p.a. average, with a 15% concessional tax rate — making it one of the most tax-efficient investment vehicles in Australia.