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Compound Interest Calculator

Project savings and investment growth with compound interest, regular contributions and inflation adjustment.

Works offlineFinance

Your plan

%

Long-run global equities have averaged roughly 7% after inflation.

20 years

Discounts the final balance by inflation, which is usually the figure that actually matters.

Growth over time

The lower band is what you put in; the upper band is what the return earned on top.

  • What you paid in
  • Interest earned

Year by year

The same figures as the chart, in full.

Contributions, interest and balance for each year
YearPaid inInterestBalance
1$13,000.00$839.12$13,839.12
2$16,000.00$1,955.77$17,955.77
3$19,000.00$3,370.01$22,370.01
4$22,000.00$5,103.36$27,103.36
5$25,000.00$7,178.88$32,178.88
6$28,000.00$9,621.32$37,621.32
7$31,000.00$12,457.18$43,457.18
8$34,000.00$15,714.93$49,714.93
9$37,000.00$19,425.04$56,425.04
10$40,000.00$23,620.23$63,620.23
11$43,000.00$28,335.56$71,335.56
12$46,000.00$33,608.63$79,608.63
13$49,000.00$39,479.77$88,479.77
14$52,000.00$45,992.20$97,992.20
15$55,000.00$53,192.28$108,192.28
16$58,000.00$61,129.73$119,129.73
17$61,000.00$69,857.84$130,857.84
18$64,000.00$79,433.78$143,433.78
19$67,000.00$89,918.84$156,918.84
20$70,000.00$101,378.74$171,378.74
Balance after 20 years
$171,378.74
You paid in
$70,000.00
Interest earned
$101,378.74
59.2% of the final balance
Growth multiple
2.45×
final balance ÷ what you paid in

Contributions vs growth

41%
59%
  • What you paid in
  • Interest earned
This is arithmetic on the assumptions you entered, not a forecast. Real returns vary year to year, and a steady average hides sequences that matter a great deal if you need the money at a fixed time.

About the compound interest calculator

Model how a balance grows from a starting amount, a regular contribution and a rate of return, with the compounding frequency configurable from annual to daily. A stacked chart separates what you put in from what the interest earned, and a year-by-year table gives the detail. An optional inflation rate shows the result in today's money, which is usually the number that actually matters.

This tool runs entirely in your browser. Nothing you type is uploaded, and it keeps working with no connection at all — including as an installed app.