📈 Compound Interest

$10,000 at 9% for 20 Years

Investing $10,000 at 9% annual compound interest for 20 years grows to $56,044. That's $46,044 earned in interest on top of your original $10,000.

If you want to adjust the return assumption, extend the timeframe, or add regular contributions, use the compound interest calculator.

If you want the plain-English explanation behind the numbers, read our guide to compound interest.

Compound Interest Calculator
Australia 2026
$
%
$
Total value after 20 years
$56,044
Amount invested$10,000
Interest earned$46,044
Interest multiplier5.60×
Year-by-year growth
YearBalanceInterest
Yr 1$10,900+$900
Yr 2$11,881+$981
Yr 3$12,950+$1,069
Yr 4$14,116+$1,166
Yr 5$15,386+$1,270
Yr 6$16,771+$1,385
Yr 7$18,280+$1,509
Yr 8$19,926+$1,645
Yr 9$21,719+$1,793
Yr 10$23,674+$1,955
Yr 11$25,804+$2,131
Yr 12$28,127+$2,322
Yr 13$30,658+$2,531
Yr 14$33,417+$2,759
Yr 15$36,425+$3,008
Yr 16$39,703+$3,278
Yr 17$43,276+$3,573
Yr 18$47,171+$3,895
Yr 19$51,417+$4,245
Yr 20$56,044+$4,627
Final balance after 20 years
$56,044
Invested
$10,000
Interest earned
$46,044
Multiplier
5.60×

How $10,000 grows at 9%

Compound interest earns returns on your returns — not just your original investment. At 9% per year, your money doubles every 8 years (the Rule of 72). Over 20 years, that compounds to a 5.60× multiplier.

In year 1, $10,000 earns $900 in interest. By year 20, the annual interest has grown to $4,627 — because each year's interest is calculated on a larger balance.

This is why longer holding periods matter so much. The later years do more of the heavy lifting, especially once the balance is large enough to generate bigger dollar returns each year.

$10,000 for 20 years at different rates
RateFinal balanceInterest earnedMultiplier
4%$21,911$11,9112.19×
5%$26,533$16,5332.65×
6%$32,071$22,0713.21×
7%$38,697$28,6973.87×
8%$46,610$36,6104.66×
9% ◀$56,044$46,0445.60×
10%$67,275$57,2756.73×

Year-by-year projection

YearBalanceInterest this yearTotal interestGrowth
Year 1$10,900+$900$9001.09×
Year 2$11,881+$981$1,8811.19×
Year 3$12,950+$1,069$2,9501.30×
Year 4$14,116+$1,166$4,1161.41×
Year 5$15,386+$1,270$5,3861.54×
Year 6$16,771+$1,385$6,7711.68×
Year 7$18,280+$1,509$8,2801.83×
Year 8$19,926+$1,645$9,9261.99×
Year 9$21,719+$1,793$11,7192.17×
Year 10$23,674+$1,955$13,6742.37×
Year 11$25,804+$2,131$15,8042.58×
Year 12$28,127+$2,322$18,1272.81×
Year 13$30,658+$2,531$20,6583.07×
Year 14$33,417+$2,759$23,4173.34×
Year 15$36,425+$3,008$26,4253.64×
Year 16$39,703+$3,278$29,7033.97×
Year 17$43,276+$3,573$33,2764.33×
Year 18$47,171+$3,895$37,1714.72×
Year 19$51,417+$4,245$41,4175.14×
Year 20$56,044+$4,627$46,0445.60×

Growth chart

Balance growth over 20 years
$14k$28k$42k$56kYr1Yr5Yr10Yr15Yr20
Principal
Interest earned

Frequently asked questions

Related compound interest scenarios

Use these nearby examples to compare what changes when you keep the same starting balance, extend the investing period, or test a more aggressive return assumption.

Compound interest guide and tools

Related calculators