📈 Compound Interest

$100,000 at 7% for 30 Years

Investing $100,000 at 7% annual compound interest for 30 years grows to $761,226. That's $661,226 earned in interest on top of your original $100,000.

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
$761,226
Amount invested$100,000
Interest earned$661,226
Interest multiplier7.61×
Year-by-year growth
YearBalanceInterest
Yr 1$107,000+$7,000
Yr 2$114,490+$7,490
Yr 3$122,504+$8,014
Yr 4$131,080+$8,575
Yr 5$140,255+$9,176
Yr 6$150,073+$9,818
Yr 7$160,578+$10,505
Yr 8$171,819+$11,240
Yr 9$183,846+$12,027
Yr 10$196,715+$12,869
Yr 11$210,485+$13,770
Yr 12$225,219+$14,734
Yr 13$240,985+$15,765
Yr 14$257,853+$16,869
Yr 15$275,903+$18,050
Yr 16$295,216+$19,313
Yr 17$315,882+$20,665
Yr 18$337,993+$22,112
Yr 19$361,653+$23,660
Yr 20$386,968+$25,316
Yr 21$414,056+$27,088
Yr 22$443,040+$28,984
Yr 23$474,053+$31,013
Yr 24$507,237+$33,184
Yr 25$542,743+$35,507
Yr 26$580,735+$37,992
Yr 27$621,387+$40,651
Yr 28$664,884+$43,497
Yr 29$711,426+$46,542
Yr 30$761,226+$49,800
Final balance after 30 years
$761,226
Invested
$100,000
Interest earned
$661,226
Multiplier
7.61×

How $100,000 grows at 7%

Compound interest earns returns on your returns — not just your original investment. At 7% per year, your money doubles every 10.3 years (the Rule of 72). Over 30 years, that compounds to a 7.61× multiplier.

In year 1, $100,000 earns $7,000 in interest. By year 30, the annual interest has grown to $49,800 — 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.

$100,000 for 30 years at different rates
RateFinal balanceInterest earnedMultiplier
4%$324,340$224,3403.24×
5%$432,194$332,1944.32×
6%$574,349$474,3495.74×
7% ◀$761,226$661,2267.61×
8%$1,006,266$906,26610.06×
9%$1,326,768$1,226,76813.27×
10%$1,744,940$1,644,94017.45×

Year-by-year projection

YearBalanceInterest this yearTotal interestGrowth
Year 1$107,000+$7,000$7,0001.07×
Year 2$114,490+$7,490$14,4901.14×
Year 3$122,504+$8,014$22,5041.23×
Year 4$131,080+$8,575$31,0801.31×
Year 5$140,255+$9,176$40,2551.40×
Year 6$150,073+$9,818$50,0731.50×
Year 7$160,578+$10,505$60,5781.61×
Year 8$171,819+$11,240$71,8191.72×
Year 9$183,846+$12,027$83,8461.84×
Year 10$196,715+$12,869$96,7151.97×
Year 11$210,485+$13,770$110,4852.10×
Year 12$225,219+$14,734$125,2192.25×
Year 13$240,985+$15,765$140,9852.41×
Year 14$257,853+$16,869$157,8532.58×
Year 15$275,903+$18,050$175,9032.76×
Year 16$295,216+$19,313$195,2162.95×
Year 17$315,882+$20,665$215,8823.16×
Year 18$337,993+$22,112$237,9933.38×
Year 19$361,653+$23,660$261,6533.62×
Year 20$386,968+$25,316$286,9683.87×
Year 21$414,056+$27,088$314,0564.14×
Year 22$443,040+$28,984$343,0404.43×
Year 23$474,053+$31,013$374,0534.74×
Year 24$507,237+$33,184$407,2375.07×
Year 25$542,743+$35,507$442,7435.43×
Year 26$580,735+$37,992$480,7355.81×
Year 27$621,387+$40,651$521,3876.21×
Year 28$664,884+$43,497$564,8846.65×
Year 29$711,426+$46,542$611,4267.11×
Year 30$761,226+$49,800$661,2267.61×

Growth chart

Balance growth over 30 years
$190k$381k$571k$761kYr1Yr5Yr10Yr15Yr20Yr25Yr30
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

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