Savings Accrual Calculator, CD Accrual

Entry Fields

Staring Amount - Also referred to as principal, enter the amount of the initial deposit when you opened the account. If you are simulating interest compounding over multiple terms, enter the projected initial principal.

You can specify up to 8 different terms. For each, enter the following:

Term Length - The term is defined by the financial institution, and defines how long your principal is to remain in the account during which time it earns the APY interest rate.

APY (%) - Annual Percentage Yield of the CD for this term.

Compound Frequency - How often the interest is compounded on the CD. Select from list: daily, monthly, quarterly or annually.

About Savings/CD Accrual Calculator

This calculator is helpful to watch your money grow over time as the APY rates have changed or you've updated term lengths since your compounding account was opened.

When you open a certificate of deposit, it's based on a term length throughout which the APY at the time of opening remains in effect. Compounded interest is then added to your balance at the CD's defined interval (e.g. daily or quarterly).

Once the CD reaches maturity (i.e. the term length is reached), you usually have the option* of closing the CD, withdrawing some of the balance, adding money into the account, or changing the term. Whether you keep the same term length or change it, more than likely the APY will be different.

If you've been keeping track of the APY and term changes throughout the life of your deposit account (e.g. in a spreadsheet), use this calculator to see how your principal has increased via compounded interest at each new term.

If you know the current balance of your deposit account, but have not kept track of the interim increases as each term matured, this calculator can show you estimated balances as each term ended, provided you know the term lengths and APY per term.

And, of course, you can use this accrual calculator to simulate interest earnings based on current trends and rate change predictions. For example, from mid 2022 through July 2023, the Federal Reserve raised the Fund Rate 11 times, and subsequent to each, many financial institutions increased both their savings account and CD APY rates. It's projected rates will likely go down in 2024. So you might simulate opening a CD with a short term (3 months) at the current rate, followed by a slightly longer term (6 months) in early 2024 at the APY you (or others) project, and a longer term (1 year) later in 2024, again based on predictions.

* What options are actually available to you at maturity varies by financial institution.

Formula to compound interest is

The formula for compounding interest for each term listed is shown below. Starting with the first term listed, the start amount specified is used to compound interest. On each additional term you've listed, the starting balance is the ending balance of the previous term. Assuming your CD has the provision to renew your CD at maturity at the then current APY (or you have the ability to change the term), this is typically similar to how your financial institution does ongoing accrual.

After all terms you've specified are compounded, the final balance is shown, along with the total interest earned, which is the difference between the starting amount and the final amount: