📈 Compound Interest
$100,000 at 4% for 30 Years
Investing $100,000 at 4% annual compound interest for 30 years grows to $324,340. That's $224,340 earned in interest on top of your original $100,000.
Compound Interest Calculator
Australia 2026
$
%
$
Total value after 30 years
$324,340
Amount invested$100,000
Interest earned$224,340
Interest multiplier3.24×
Year-by-year growth
| Year | Balance | Interest |
|---|---|---|
| Yr 1 | $104,000 | +$4,000 |
| Yr 2 | $108,160 | +$4,160 |
| Yr 3 | $112,486 | +$4,326 |
| Yr 4 | $116,986 | +$4,499 |
| Yr 5 | $121,665 | +$4,679 |
| Yr 6 | $126,532 | +$4,867 |
| Yr 7 | $131,593 | +$5,061 |
| Yr 8 | $136,857 | +$5,264 |
| Yr 9 | $142,331 | +$5,474 |
| Yr 10 | $148,024 | +$5,693 |
| Yr 11 | $153,945 | +$5,921 |
| Yr 12 | $160,103 | +$6,158 |
| Yr 13 | $166,507 | +$6,404 |
| Yr 14 | $173,168 | +$6,660 |
| Yr 15 | $180,094 | +$6,927 |
| Yr 16 | $187,298 | +$7,204 |
| Yr 17 | $194,790 | +$7,492 |
| Yr 18 | $202,582 | +$7,792 |
| Yr 19 | $210,685 | +$8,103 |
| Yr 20 | $219,112 | +$8,427 |
| Yr 21 | $227,877 | +$8,764 |
| Yr 22 | $236,992 | +$9,115 |
| Yr 23 | $246,472 | +$9,480 |
| Yr 24 | $256,330 | +$9,859 |
| Yr 25 | $266,584 | +$10,253 |
| Yr 26 | $277,247 | +$10,663 |
| Yr 27 | $288,337 | +$11,090 |
| Yr 28 | $299,870 | +$11,533 |
| Yr 29 | $311,865 | +$11,995 |
| Yr 30 | $324,340 | +$12,475 |
Final balance after 30 years
$324,340
Invested
$100,000
Interest earned
$224,340
Multiplier
3.24×
How $100,000 grows at 4%
Compound interest earns returns on your returns — not just your original investment. At 4% per year, your money doubles every 18 years (the Rule of 72). Over 30 years, that compounds to a 3.24× multiplier.
In year 1, $100,000 earns $4,000 in interest. By year 30, the annual interest has grown to $12,475 — 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 | $104,000 | +$4,000 | $4,000 | 1.04× |
| Year 2 | $108,160 | +$4,160 | $8,160 | 1.08× |
| Year 3 | $112,486 | +$4,326 | $12,486 | 1.12× |
| Year 4 | $116,986 | +$4,499 | $16,986 | 1.17× |
| Year 5 | $121,665 | +$4,679 | $21,665 | 1.22× |
| Year 6 | $126,532 | +$4,867 | $26,532 | 1.27× |
| Year 7 | $131,593 | +$5,061 | $31,593 | 1.32× |
| Year 8 | $136,857 | +$5,264 | $36,857 | 1.37× |
| Year 9 | $142,331 | +$5,474 | $42,331 | 1.42× |
| Year 10 | $148,024 | +$5,693 | $48,024 | 1.48× |
| Year 11 | $153,945 | +$5,921 | $53,945 | 1.54× |
| Year 12 | $160,103 | +$6,158 | $60,103 | 1.60× |
| Year 13 | $166,507 | +$6,404 | $66,507 | 1.67× |
| Year 14 | $173,168 | +$6,660 | $73,168 | 1.73× |
| Year 15 | $180,094 | +$6,927 | $80,094 | 1.80× |
| Year 16 | $187,298 | +$7,204 | $87,298 | 1.87× |
| Year 17 | $194,790 | +$7,492 | $94,790 | 1.95× |
| Year 18 | $202,582 | +$7,792 | $102,582 | 2.03× |
| Year 19 | $210,685 | +$8,103 | $110,685 | 2.11× |
| Year 20 | $219,112 | +$8,427 | $119,112 | 2.19× |
| Year 21 | $227,877 | +$8,764 | $127,877 | 2.28× |
| Year 22 | $236,992 | +$9,115 | $136,992 | 2.37× |
| Year 23 | $246,472 | +$9,480 | $146,472 | 2.46× |
| Year 24 | $256,330 | +$9,859 | $156,330 | 2.56× |
| Year 25 | $266,584 | +$10,253 | $166,584 | 2.67× |
| Year 26 | $277,247 | +$10,663 | $177,247 | 2.77× |
| Year 27 | $288,337 | +$11,090 | $188,337 | 2.88× |
| Year 28 | $299,870 | +$11,533 | $199,870 | 3.00× |
| Year 29 | $311,865 | +$11,995 | $211,865 | 3.12× |
| Year 30 | $324,340 | +$12,475 | $224,340 | 3.24× |
Growth chart
Balance growth over 30 years
Principal
Interest earned
Frequently asked questions
Explore other scenarios
$100,000 for 30 years — other rates
$100,000 at 4% — other time horizons
Related calculators
Compound Interest Calculator
Australia 2026
$
%
$
Total value after 30 years
$324,340
Amount invested$100,000
Interest earned$224,340
Interest multiplier3.24×
Year-by-year growth
| Year | Balance | Interest |
|---|---|---|
| Yr 1 | $104,000 | +$4,000 |
| Yr 2 | $108,160 | +$4,160 |
| Yr 3 | $112,486 | +$4,326 |
| Yr 4 | $116,986 | +$4,499 |
| Yr 5 | $121,665 | +$4,679 |
| Yr 6 | $126,532 | +$4,867 |
| Yr 7 | $131,593 | +$5,061 |
| Yr 8 | $136,857 | +$5,264 |
| Yr 9 | $142,331 | +$5,474 |
| Yr 10 | $148,024 | +$5,693 |
| Yr 11 | $153,945 | +$5,921 |
| Yr 12 | $160,103 | +$6,158 |
| Yr 13 | $166,507 | +$6,404 |
| Yr 14 | $173,168 | +$6,660 |
| Yr 15 | $180,094 | +$6,927 |
| Yr 16 | $187,298 | +$7,204 |
| Yr 17 | $194,790 | +$7,492 |
| Yr 18 | $202,582 | +$7,792 |
| Yr 19 | $210,685 | +$8,103 |
| Yr 20 | $219,112 | +$8,427 |
| Yr 21 | $227,877 | +$8,764 |
| Yr 22 | $236,992 | +$9,115 |
| Yr 23 | $246,472 | +$9,480 |
| Yr 24 | $256,330 | +$9,859 |
| Yr 25 | $266,584 | +$10,253 |
| Yr 26 | $277,247 | +$10,663 |
| Yr 27 | $288,337 | +$11,090 |
| Yr 28 | $299,870 | +$11,533 |
| Yr 29 | $311,865 | +$11,995 |
| Yr 30 | $324,340 | +$12,475 |