📈 Compound Interest
$1,000 at 8% for 20 Years
Investing $1,000 at 8% annual compound interest for 20 years grows to $4,661. That's $3,661 earned in interest on top of your original $1,000.
Compound Interest Calculator
Australia 2026
$
%
$
Total value after 20 years
$4,661
Amount invested$1,000
Interest earned$3,661
Interest multiplier4.66×
Year-by-year growth
| Year | Balance | Interest |
|---|---|---|
| Yr 1 | $1,080 | +$80 |
| Yr 2 | $1,166 | +$86 |
| Yr 3 | $1,260 | +$93 |
| Yr 4 | $1,360 | +$101 |
| Yr 5 | $1,469 | +$109 |
| Yr 6 | $1,587 | +$118 |
| Yr 7 | $1,714 | +$127 |
| Yr 8 | $1,851 | +$137 |
| Yr 9 | $1,999 | +$148 |
| Yr 10 | $2,159 | +$160 |
| Yr 11 | $2,332 | +$173 |
| Yr 12 | $2,518 | +$187 |
| Yr 13 | $2,720 | +$201 |
| Yr 14 | $2,937 | +$218 |
| Yr 15 | $3,172 | +$235 |
| Yr 16 | $3,426 | +$254 |
| Yr 17 | $3,700 | +$274 |
| Yr 18 | $3,996 | +$296 |
| Yr 19 | $4,316 | +$320 |
| Yr 20 | $4,661 | +$345 |
Final balance after 20 years
$4,661
Invested
$1,000
Interest earned
$3,661
Multiplier
4.66×
How $1,000 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, $1,000 earns $80 in interest. By year 20, the annual interest has grown to $345 — 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 | $1,080 | +$80 | $80 | 1.08× |
| Year 2 | $1,166 | +$86 | $166 | 1.17× |
| Year 3 | $1,260 | +$93 | $260 | 1.26× |
| Year 4 | $1,360 | +$101 | $360 | 1.36× |
| Year 5 | $1,469 | +$109 | $469 | 1.47× |
| Year 6 | $1,587 | +$118 | $587 | 1.59× |
| Year 7 | $1,714 | +$127 | $714 | 1.71× |
| Year 8 | $1,851 | +$137 | $851 | 1.85× |
| Year 9 | $1,999 | +$148 | $999 | 2.00× |
| Year 10 | $2,159 | +$160 | $1,159 | 2.16× |
| Year 11 | $2,332 | +$173 | $1,332 | 2.33× |
| Year 12 | $2,518 | +$187 | $1,518 | 2.52× |
| Year 13 | $2,720 | +$201 | $1,720 | 2.72× |
| Year 14 | $2,937 | +$218 | $1,937 | 2.94× |
| Year 15 | $3,172 | +$235 | $2,172 | 3.17× |
| Year 16 | $3,426 | +$254 | $2,426 | 3.43× |
| Year 17 | $3,700 | +$274 | $2,700 | 3.70× |
| Year 18 | $3,996 | +$296 | $2,996 | 4.00× |
| Year 19 | $4,316 | +$320 | $3,316 | 4.32× |
| Year 20 | $4,661 | +$345 | $3,661 | 4.66× |
Growth chart
Balance growth over 20 years
Principal
Interest earned
Frequently asked questions
Explore other scenarios
$1,000 for 20 years — other rates
$1,000 at 8% — other time horizons
Related calculators
Compound Interest Calculator
Australia 2026
$
%
$
Total value after 20 years
$4,661
Amount invested$1,000
Interest earned$3,661
Interest multiplier4.66×
Year-by-year growth
| Year | Balance | Interest |
|---|---|---|
| Yr 1 | $1,080 | +$80 |
| Yr 2 | $1,166 | +$86 |
| Yr 3 | $1,260 | +$93 |
| Yr 4 | $1,360 | +$101 |
| Yr 5 | $1,469 | +$109 |
| Yr 6 | $1,587 | +$118 |
| Yr 7 | $1,714 | +$127 |
| Yr 8 | $1,851 | +$137 |
| Yr 9 | $1,999 | +$148 |
| Yr 10 | $2,159 | +$160 |
| Yr 11 | $2,332 | +$173 |
| Yr 12 | $2,518 | +$187 |
| Yr 13 | $2,720 | +$201 |
| Yr 14 | $2,937 | +$218 |
| Yr 15 | $3,172 | +$235 |
| Yr 16 | $3,426 | +$254 |
| Yr 17 | $3,700 | +$274 |
| Yr 18 | $3,996 | +$296 |
| Yr 19 | $4,316 | +$320 |
| Yr 20 | $4,661 | +$345 |