Compound Interest
Calculate the future value of an investment with compound interest over time.
Results
What is it?
Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. Unlike simple interest, your money grows exponentially over time — often called "the eighth wonder of the world" by investors.
How to use
Enter your initial deposit (principal), the annual interest rate, how often interest compounds (monthly is most common for savings accounts), and how many years you plan to invest. The calculator instantly shows your total balance and how much of it is pure interest.
Example scenario
If you invest $10,000 at 5% annual interest compounded monthly for 10 years, your investment grows to $16,470.09 — earning $6,470.09 in interest without any additional deposits.
Pro tip
The more frequently interest compounds, the more you earn. Daily compounding at 5% yields an effective annual rate of 5.13%, compared to 5.09% for monthly. Over decades, this difference compounds into thousands of dollars.