📈 Compound Interest

$100,000 at 6% for 20 Years

Investing $100,000 at 6% annual compound interest for 20 years grows to $320,714. That's $220,714 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 20 years
$320,714
Amount invested$100,000
Interest earned$220,714
Interest multiplier3.21×
Year-by-year growth
YearBalanceInterest
Yr 1$106,000+$6,000
Yr 2$112,360+$6,360
Yr 3$119,102+$6,742
Yr 4$126,248+$7,146
Yr 5$133,823+$7,575
Yr 6$141,852+$8,029
Yr 7$150,363+$8,511
Yr 8$159,385+$9,022
Yr 9$168,948+$9,563
Yr 10$179,085+$10,137
Yr 11$189,830+$10,745
Yr 12$201,220+$11,390
Yr 13$213,293+$12,073
Yr 14$226,090+$12,798
Yr 15$239,656+$13,565
Yr 16$254,035+$14,379
Yr 17$269,277+$15,242
Yr 18$285,434+$16,157
Yr 19$302,560+$17,126
Yr 20$320,714+$18,154
Final balance after 20 years
$320,714
Invested
$100,000
Interest earned
$220,714
Multiplier
3.21×

How $100,000 grows at 6%

Compound interest earns returns on your returns — not just your original investment. At 6% per year, your money doubles every 12 years (the Rule of 72). Over 20 years, that compounds to a 3.21× multiplier.

In year 1, $100,000 earns $6,000 in interest. By year 20, the annual interest has grown to $18,154 — 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 20 years at different rates
RateFinal balanceInterest earnedMultiplier
4%$219,112$119,1122.19×
5%$265,330$165,3302.65×
6% ◀$320,714$220,7143.21×
7%$386,968$286,9683.87×
8%$466,096$366,0964.66×
9%$560,441$460,4415.60×
10%$672,750$572,7506.73×

Year-by-year projection

YearBalanceInterest this yearTotal interestGrowth
Year 1$106,000+$6,000$6,0001.06×
Year 2$112,360+$6,360$12,3601.12×
Year 3$119,102+$6,742$19,1021.19×
Year 4$126,248+$7,146$26,2481.26×
Year 5$133,823+$7,575$33,8231.34×
Year 6$141,852+$8,029$41,8521.42×
Year 7$150,363+$8,511$50,3631.50×
Year 8$159,385+$9,022$59,3851.59×
Year 9$168,948+$9,563$68,9481.69×
Year 10$179,085+$10,137$79,0851.79×
Year 11$189,830+$10,745$89,8301.90×
Year 12$201,220+$11,390$101,2202.01×
Year 13$213,293+$12,073$113,2932.13×
Year 14$226,090+$12,798$126,0902.26×
Year 15$239,656+$13,565$139,6562.40×
Year 16$254,035+$14,379$154,0352.54×
Year 17$269,277+$15,242$169,2772.69×
Year 18$285,434+$16,157$185,4342.85×
Year 19$302,560+$17,126$202,5603.03×
Year 20$320,714+$18,154$220,7143.21×

Growth chart

Balance growth over 20 years
$80k$160k$241k$321kYr1Yr5Yr10Yr15Yr20
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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