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Compound Interest Calculator

Principal Amount ($)

Interest Rate (%)

Compounding Frequency

Time Period

Number of Days

Number of Months

Start Date

End Date

Exclude Weekends

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How to Use the Compound Interest Calculator

Planning your financial future shouldn't be complicated. Follow these simple steps to project your investment growth:

1
Initial Investment (Principal) Enter the amount of money you are starting with.
2
Monthly Contribution Input optional recurring deposits to see how they accelerate growth.
3
Interest Rate Enter your expected APR. Historical market averages are around 7% to 10%.
4
Investment Term Choose the number of years you plan to let your money grow.
5
Compounding Frequency Choose Monthly, Quarterly, or Annually to see the impact of frequency.
6
Calculate Hit the button for a full year-by-year breakdown!

The Compound Interest Formula: How It Works

The "magic" of compounding happens because you earn interest not only on your original principal but also on the interest that has already been added to your account.

The Standard Formula

$$A = P \left(1 + \frac{r}{n}\right)^{nt}$$

Variable Definitions

$A$ Final Amount (Future Value)

$P$ Initial Principal Deposit

$r$ Annual Interest Rate (decimal)

$n$ Compounds per Year

$t$ Number of Years

Example in Action

If you invest $1,000 at 5% interest compounded annually for 10 years:

$$A = 1,000 \left(1 + \frac{0.05}{1}\right)^{(1 \times 10)}$$

$$A = 1,000 \times (1.05)^{10}$$

$$A \approx \$1,628.89$$

By the end of 10 years, you would have earned $628.89 in interest just by letting your money sit!