📈 Compound Interest

$20,000 at 7% for 10 Years

Investing $20,000 at 7% annual compound interest for 10 years grows to $39,343. That's $19,343 earned in interest on top of your original $20,000.

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 10 years
$39,343
Amount invested$20,000
Interest earned$19,343
Interest multiplier1.97×
Year-by-year growth
YearBalanceInterest
Yr 1$21,400+$1,400
Yr 2$22,898+$1,498
Yr 3$24,501+$1,603
Yr 4$26,216+$1,715
Yr 5$28,051+$1,835
Yr 6$30,015+$1,964
Yr 7$32,116+$2,101
Yr 8$34,364+$2,248
Yr 9$36,769+$2,405
Yr 10$39,343+$2,574
Final balance after 10 years
$39,343
Invested
$20,000
Interest earned
$19,343
Multiplier
1.97×

How $20,000 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 10 years, that compounds to a 1.97× multiplier.

In year 1, $20,000 earns $1,400 in interest. By year 10, the annual interest has grown to $2,574 — 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.

$20,000 for 10 years at different rates
RateFinal balanceInterest earnedMultiplier
4%$29,605$9,6051.48×
5%$32,578$12,5781.63×
6%$35,817$15,8171.79×
7% ◀$39,343$19,3431.97×
8%$43,178$23,1782.16×
9%$47,347$27,3472.37×
10%$51,875$31,8752.59×

Year-by-year projection

YearBalanceInterest this yearTotal interestGrowth
Year 1$21,400+$1,400$1,4001.07×
Year 2$22,898+$1,498$2,8981.14×
Year 3$24,501+$1,603$4,5011.23×
Year 4$26,216+$1,715$6,2161.31×
Year 5$28,051+$1,835$8,0511.40×
Year 6$30,015+$1,964$10,0151.50×
Year 7$32,116+$2,101$12,1161.61×
Year 8$34,364+$2,248$14,3641.72×
Year 9$36,769+$2,405$16,7691.84×
Year 10$39,343+$2,574$19,3431.97×

Growth chart

Balance growth over 10 years
$10k$20k$30k$39kYr1Yr5Yr10
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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