Compound Interest Calculator

By Pam O’Brien | Updated Sept 6, 2024

Compound interest has been referred to as “the 8th wonder of the world” (Albert Einstein has been credited with calling it that), and it can be a valuable tool for growing your savings. Using a compound interest calculator can help illustrate the power of compound interest.

Compound interest is different from simple interest. Simple interest is the interest that accrues on an initial amount of money deposited in a savings account, known as the principal.

With compound interest, the interest is added to the principal amount, and interest is then earned on the principal plus the added interest over time. In other words, you’re not only earning interest on the principal — you’re also earning interest on the interest.

With compound interest, your money can grow faster, depending how often the interest is calculated. And over time, you can typically save significantly more with compound interest than you can with simple interest.

A compound interest calculator can help show you the value of saving early and regularly. Read on to learn more about using a compound interest calculator.

*Actual interest credited by your financial institution may vary based on institution-specific calculation methodology.

Calculator Definitions

Before using a compound interest calculator, it’s important to understand the different metrics you’ll need to fill in. They are:

• Initial Deposit: The amount of money you first put into your interest earning account. It represents the starting point of your investment journey. The larger it is, the more you can earn from interest. In addition, some financial institutions require a specific dollar amount for your first deposit to open the account or secure a higher interest rate.

• Monthly Contribution: The amount of money you expect to add to the account each month.

• Time to Grow: The number of years and months you plan to save the money in the account so it can grow

• Expected Rate of Return: What you estimate the interest rate for the account will be.

• Compound Frequency: The number of times per year that the interest will be calculated and compounded on the account. Depending on the account, interest might be compounded daily, monthly, quarterly, or annually, for instance.

• Interest Earned: The total amount of interest that accumulates on your initial deposit and any additional contributions over the specified time period. You can calculate this figure with the estimated rate of return, the compounding frequency, and the time elapsed. Higher interest rates create more earnings.

• Total Contributions: Total contributions represent the sum of your initial deposit and all the monthly contributions made over the specified time period. It gives you a clear picture of how much money you have contributed to the account.