📈 Compound Interest

$10,000 at 8% for 30 Years

Investing $10,000 at 8% annual compound interest for 30 years grows to $100,627. That's $90,627 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
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%
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Total value after 30 years
$100,627
Amount invested$10,000
Interest earned$90,627
Interest multiplier10.06×
Year-by-year growth
YearBalanceInterest
Yr 1$10,800+$800
Yr 2$11,664+$864
Yr 3$12,597+$933
Yr 4$13,605+$1,008
Yr 5$14,693+$1,088
Yr 6$15,869+$1,175
Yr 7$17,138+$1,269
Yr 8$18,509+$1,371
Yr 9$19,990+$1,481
Yr 10$21,589+$1,599
Yr 11$23,316+$1,727
Yr 12$25,182+$1,865
Yr 13$27,196+$2,015
Yr 14$29,372+$2,176
Yr 15$31,722+$2,350
Yr 16$34,259+$2,538
Yr 17$37,000+$2,741
Yr 18$39,960+$2,960
Yr 19$43,157+$3,197
Yr 20$46,610+$3,453
Yr 21$50,338+$3,729
Yr 22$54,365+$4,027
Yr 23$58,715+$4,349
Yr 24$63,412+$4,697
Yr 25$68,485+$5,073
Yr 26$73,964+$5,479
Yr 27$79,881+$5,917
Yr 28$86,271+$6,390
Yr 29$93,173+$6,902
Yr 30$100,627+$7,454
Final balance after 30 years
$100,627
Invested
$10,000
Interest earned
$90,627
Multiplier
10.06×

How $10,000 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 30 years, that compounds to a 10.06× multiplier.

In year 1, $10,000 earns $800 in interest. By year 30, the annual interest has grown to $7,454 — 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 30 years at different rates
RateFinal balanceInterest earnedMultiplier
4%$32,434$22,4343.24×
5%$43,219$33,2194.32×
6%$57,435$47,4355.74×
7%$76,123$66,1237.61×
8% ◀$100,627$90,62710.06×
9%$132,677$122,67713.27×
10%$174,494$164,49417.45×

Year-by-year projection

YearBalanceInterest this yearTotal interestGrowth
Year 1$10,800+$800$8001.08×
Year 2$11,664+$864$1,6641.17×
Year 3$12,597+$933$2,5971.26×
Year 4$13,605+$1,008$3,6051.36×
Year 5$14,693+$1,088$4,6931.47×
Year 6$15,869+$1,175$5,8691.59×
Year 7$17,138+$1,269$7,1381.71×
Year 8$18,509+$1,371$8,5091.85×
Year 9$19,990+$1,481$9,9902.00×
Year 10$21,589+$1,599$11,5892.16×
Year 11$23,316+$1,727$13,3162.33×
Year 12$25,182+$1,865$15,1822.52×
Year 13$27,196+$2,015$17,1962.72×
Year 14$29,372+$2,176$19,3722.94×
Year 15$31,722+$2,350$21,7223.17×
Year 16$34,259+$2,538$24,2593.43×
Year 17$37,000+$2,741$27,0003.70×
Year 18$39,960+$2,960$29,9604.00×
Year 19$43,157+$3,197$33,1574.32×
Year 20$46,610+$3,453$36,6104.66×
Year 21$50,338+$3,729$40,3385.03×
Year 22$54,365+$4,027$44,3655.44×
Year 23$58,715+$4,349$48,7155.87×
Year 24$63,412+$4,697$53,4126.34×
Year 25$68,485+$5,073$58,4856.85×
Year 26$73,964+$5,479$63,9647.40×
Year 27$79,881+$5,917$69,8817.99×
Year 28$86,271+$6,390$76,2718.63×
Year 29$93,173+$6,902$83,1739.32×
Year 30$100,627+$7,454$90,62710.06×

Growth chart

Balance growth over 30 years
$25k$50k$75k$101kYr1Yr5Yr10Yr15Yr20Yr25Yr30
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.

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