📈 Compound Interest

$200,000 at 4% for 20 Years

Investing $200,000 at 4% annual compound interest for 20 years grows to $438,225. That's $238,225 earned in interest on top of your original $200,000.

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 20 years
$438,225
Amount invested$200,000
Interest earned$238,225
Interest multiplier2.19×
Year-by-year growth
YearBalanceInterest
Yr 1$208,000+$8,000
Yr 2$216,320+$8,320
Yr 3$224,973+$8,653
Yr 4$233,972+$8,999
Yr 5$243,331+$9,359
Yr 6$253,064+$9,733
Yr 7$263,186+$10,123
Yr 8$273,714+$10,527
Yr 9$284,662+$10,949
Yr 10$296,049+$11,386
Yr 11$307,891+$11,842
Yr 12$320,206+$12,316
Yr 13$333,015+$12,808
Yr 14$346,335+$13,321
Yr 15$360,189+$13,853
Yr 16$374,596+$14,408
Yr 17$389,580+$14,984
Yr 18$405,163+$15,583
Yr 19$421,370+$16,207
Yr 20$438,225+$16,855
Final balance after 20 years
$438,225
Invested
$200,000
Interest earned
$238,225
Multiplier
2.19×

How $200,000 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 20 years, that compounds to a 2.19× multiplier.

In year 1, $200,000 earns $8,000 in interest. By year 20, the annual interest has grown to $16,855 — 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.

$200,000 for 20 years at different rates
RateFinal balanceInterest earnedMultiplier
4% ◀$438,225$238,2252.19×
5%$530,660$330,6602.65×
6%$641,427$441,4273.21×
7%$773,937$573,9373.87×
8%$932,191$732,1914.66×
9%$1,120,882$920,8825.60×
10%$1,345,500$1,145,5006.73×

Year-by-year projection

YearBalanceInterest this yearTotal interestGrowth
Year 1$208,000+$8,000$8,0001.04×
Year 2$216,320+$8,320$16,3201.08×
Year 3$224,973+$8,653$24,9731.12×
Year 4$233,972+$8,999$33,9721.17×
Year 5$243,331+$9,359$43,3311.22×
Year 6$253,064+$9,733$53,0641.27×
Year 7$263,186+$10,123$63,1861.32×
Year 8$273,714+$10,527$73,7141.37×
Year 9$284,662+$10,949$84,6621.42×
Year 10$296,049+$11,386$96,0491.48×
Year 11$307,891+$11,842$107,8911.54×
Year 12$320,206+$12,316$120,2061.60×
Year 13$333,015+$12,808$133,0151.67×
Year 14$346,335+$13,321$146,3351.73×
Year 15$360,189+$13,853$160,1891.80×
Year 16$374,596+$14,408$174,5961.87×
Year 17$389,580+$14,984$189,5801.95×
Year 18$405,163+$15,583$205,1632.03×
Year 19$421,370+$16,207$221,3702.11×
Year 20$438,225+$16,855$238,2252.19×

Growth chart

Balance growth over 20 years
$110k$219k$329k$438kYr1Yr5Yr10Yr15Yr20
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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