📈 Compound Interest
$500 at 8% for 20 Years
Investing $500 at 8% annual compound interest for 20 years grows to $2,330. That's $1,830 earned in interest on top of your original $500.
Compound Interest Calculator
Australia 2026
$
%
$
Total value after 20 years
$2,330
Amount invested$500
Interest earned$1,830
Interest multiplier4.66×
Year-by-year growth
| Year | Balance | Interest |
|---|---|---|
| Yr 1 | $540 | +$40 |
| Yr 2 | $583 | +$43 |
| Yr 3 | $630 | +$47 |
| Yr 4 | $680 | +$50 |
| Yr 5 | $735 | +$54 |
| Yr 6 | $793 | +$59 |
| Yr 7 | $857 | +$63 |
| Yr 8 | $925 | +$69 |
| Yr 9 | $1,000 | +$74 |
| Yr 10 | $1,079 | +$80 |
| Yr 11 | $1,166 | +$86 |
| Yr 12 | $1,259 | +$93 |
| Yr 13 | $1,360 | +$101 |
| Yr 14 | $1,469 | +$109 |
| Yr 15 | $1,586 | +$117 |
| Yr 16 | $1,713 | +$127 |
| Yr 17 | $1,850 | +$137 |
| Yr 18 | $1,998 | +$148 |
| Yr 19 | $2,158 | +$160 |
| Yr 20 | $2,330 | +$173 |
Final balance after 20 years
$2,330
Invested
$500
Interest earned
$1,830
Multiplier
4.66×
How $500 grows at 8%
Compound interest earns returns on your returns — not just your original investment. At 8% per year, your money doubles every 9 years (the Rule of 72). Over 20 years, that compounds to a 4.66× multiplier.
In year 1, $500 earns $40 in interest. By year 20, the annual interest has grown to $173 — because each year's interest is calculated on a larger balance.
Year-by-year projection
| Year | Balance | Interest this year | Total interest | Growth |
|---|---|---|---|---|
| Year 1 | $540 | +$40 | $40 | 1.08× |
| Year 2 | $583 | +$43 | $83 | 1.17× |
| Year 3 | $630 | +$47 | $130 | 1.26× |
| Year 4 | $680 | +$50 | $180 | 1.36× |
| Year 5 | $735 | +$54 | $235 | 1.47× |
| Year 6 | $793 | +$59 | $293 | 1.59× |
| Year 7 | $857 | +$63 | $357 | 1.71× |
| Year 8 | $925 | +$69 | $425 | 1.85× |
| Year 9 | $1,000 | +$74 | $500 | 2.00× |
| Year 10 | $1,079 | +$80 | $579 | 2.16× |
| Year 11 | $1,166 | +$86 | $666 | 2.33× |
| Year 12 | $1,259 | +$93 | $759 | 2.52× |
| Year 13 | $1,360 | +$101 | $860 | 2.72× |
| Year 14 | $1,469 | +$109 | $969 | 2.94× |
| Year 15 | $1,586 | +$117 | $1,086 | 3.17× |
| Year 16 | $1,713 | +$127 | $1,213 | 3.43× |
| Year 17 | $1,850 | +$137 | $1,350 | 3.70× |
| Year 18 | $1,998 | +$148 | $1,498 | 4.00× |
| Year 19 | $2,158 | +$160 | $1,658 | 4.32× |
| Year 20 | $2,330 | +$173 | $1,830 | 4.66× |
Growth chart
Balance growth over 20 years
Principal
Interest earned
Frequently asked questions
Explore other scenarios
$500 for 20 years — other rates
$500 at 8% — other time horizons
Related calculators
Compound Interest Calculator
Australia 2026
$
%
$
Total value after 20 years
$2,330
Amount invested$500
Interest earned$1,830
Interest multiplier4.66×
Year-by-year growth
| Year | Balance | Interest |
|---|---|---|
| Yr 1 | $540 | +$40 |
| Yr 2 | $583 | +$43 |
| Yr 3 | $630 | +$47 |
| Yr 4 | $680 | +$50 |
| Yr 5 | $735 | +$54 |
| Yr 6 | $793 | +$59 |
| Yr 7 | $857 | +$63 |
| Yr 8 | $925 | +$69 |
| Yr 9 | $1,000 | +$74 |
| Yr 10 | $1,079 | +$80 |
| Yr 11 | $1,166 | +$86 |
| Yr 12 | $1,259 | +$93 |
| Yr 13 | $1,360 | +$101 |
| Yr 14 | $1,469 | +$109 |
| Yr 15 | $1,586 | +$117 |
| Yr 16 | $1,713 | +$127 |
| Yr 17 | $1,850 | +$137 |
| Yr 18 | $1,998 | +$148 |
| Yr 19 | $2,158 | +$160 |
| Yr 20 | $2,330 | +$173 |