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Compound Interest Calculator

See exactly how your money grows over time with the power of compounding. Adjust any variable and watch your wealth build instantly.

Investment Details
$
$0$500K
$
$0$5,000
%
1%20%
years
1 yr50 yrs
Growth Results
$0
Future Value
$0
Total Contributions
$0
Interest Earned
0%
Total Return
0x
your money grows by this factor
Contributions
Interest
Growth over time
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Year-by-Year Breakdown
YearContributionsInterestTotal Value
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How to use the compound interest calculator

1

Enter your investment

Input your starting amount, monthly contribution, interest rate, and how long you plan to invest.

2

Choose compounding

Select how often interest compounds — daily compounding produces slightly more growth than annual.

3

See your growth

The chart and year-by-year table show exactly how your money grows and how much comes from interest vs contributions.

Frequently asked questions

What is compound interest?
Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. Unlike simple interest, compound interest grows exponentially over time — this is why Albert Einstein reportedly called it the eighth wonder of the world.
How often should interest compound?
More frequent compounding produces slightly higher returns. Daily compounding earns a bit more than monthly, which earns more than annual. In practice, the difference between daily and monthly compounding is small for most investments.
What interest rate should I use?
The S&P 500 has historically returned about 10% annually before inflation, or about 7% after inflation. High-yield savings accounts currently offer 4-5%. Your actual rate will depend on where you invest.
Is this calculator free?
Yes — completely free with no account or signup required.