Compound Interest Calculator

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Finance & Business

Compound Interest Calculator

Project your investment growth with initial deposit, monthly contributions, and compounding frequency.

Initial Investment
$
0 $1000000 $
Monthly Contribution
$
0 $10000 $
Interest Rate
%
0 %75 %
Investment Term
yr
1 yr60 yr
Total Balance
$300,851
After 20 years at 7%
Total Principal Invested
$130,000
Total Interest Earned
$170,851

Yearly Breakdown — First 10 Years

YearPrincipalInterest EarnedTotal Balance
1$16,000-$9,081$16,919
2$6,000$1,419$24,339
3$6,000$1,956$32,294
4$6,000$2,531$40,825
5$6,000$3,148$49,973
6$6,000$3,809$59,782
7$6,000$4,518$70,299
8$6,000$5,278$81,578
9$6,000$6,094$93,671
10$6,000$6,968$106,639

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How this compound interest calculator works

This compound interest calculator projects the future value of an investment using the standard compound-interest-with-contributions formula: A = P(1 + r/n)nt + PMT × [((1 + r/n)nt − 1) / (r/n)], where P is your Initial Principal, r is the annual interest rate, n is the number of compounding periods per year, t is the time horizon in years, and PMT is the contribution made each compounding period. Your monthly contribution is automatically converted to match the Compounding Frequency you select, so the math stays accurate whether you compound daily, monthly, quarterly, or annually. When Daily is selected, n is set to 365 compounding periods per year.

Because this investment growth calculator uses a closed-form formula rather than a per-period loop, switching to Daily compounding (n = 365) recalculates instantly without runtime errors, even over long horizons. The resulting Annual Percentage Yield (APY) rises with more frequent compounding, so you can compare Daily, Monthly, Quarterly, and Annually side by side to see how compounding frequency affects your total balance.

Tips for growing your investment

  • Start early — the longer your money compounds, the more dramatic the growth, thanks to interest earning interest.
  • Even small increases in your monthly contribution can add up to tens of thousands over decades.
  • More frequent compounding (daily or monthly vs. annually) boosts returns, especially over long horizons.
  • Reinvest dividends and interest rather than withdrawing them to keep the compounding cycle intact.
  • Remember these are nominal figures — subtract 2–3% for an inflation-adjusted (real) estimate.

Looking to invest your accumulated wealth into real estate? Calculate your potential home loan payments with our Mortgage Calculator.

Frequently Asked Questions about Compound Interest

This calculator uses the standard compound interest formula with contributions: A = P(1 + r/n)^(nt) + PMT × [((1 + r/n)^(nt) − 1) / (r/n)], where P is the initial investment, r is the annual interest rate (as a decimal), n is the number of compounding periods per year, t is the number of years, and PMT is the contribution made each compounding period. Your monthly contribution is converted to a per-period amount based on the compounding frequency you select — for daily compounding n is set to 365.
The more frequently interest is compounded, the faster your money grows. Daily compounding (n = 365) earns interest on interest every day, monthly compounding (n = 12) twelve times a year, while annual compounding (n = 1) only credits interest once. Over long horizons the difference can be significant — on a 30-year investment, daily compounding can outpace annual compounding by several percent of total return.
No. This calculator shows nominal growth, meaning it does not account for inflation eroding purchasing power or for capital-gains and income taxes on your earnings. For a realistic real-world estimate, consider subtracting an assumed inflation rate (commonly 2–3% per year) and consulting a tax professional about your jurisdiction's investment tax rules.
Historically, broad stock-market index funds have averaged roughly 7–10% annual returns before inflation, while high-yield savings accounts and bonds typically yield 1–5%. Returns above 10% are aggressive assumptions and should be treated as optimistic scenarios, not guarantees. Always diversify and consider your risk tolerance.
APR (Annual Percentage Rate) reflects the simple yearly interest rate without compounding, while Annual Percentage Yield (APY) accounts for the effect of compounding frequency within the year. The more often interest compounds (daily vs. annually), the larger the gap between APR and APY — APY is always equal to or higher than APR. This investment growth calculator reports nominal growth based on your chosen compounding frequency, so switching between Daily and Annually lets you see the APY difference directly.
Calculations based on official Google AdSense Terms and Revenue Documentation.Google AdSense Help
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Total Balance$300,851