APY, or Annual Percentage Yield, represents the real rate of return on a CD over one year. Unlike the nominal interest rate, APY accounts for the effect of compounding interest, meaning it reflects the total amount of interest you will actually earn.

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CD Calculator: Estimate Your Earnings

Q: How is CD interest calculated?

CD interest is typically calculated using the compound interest formula: A = P(1 + r/n)^nt. This formula accounts for the principal deposit, the annual interest rate, the compounding frequency, and the length of the term. Some banks may also use a simple daily interest calculation for short-term accounts.

Q: How are CDs compounded at FSB?

FSB Certificates of Deposit (CDs) generally compound interest quarterly. This interest is calculated using the daily balance method and is credited to the account every three months. For shorter terms, interest may be credited at maturity.

Q: What happens to CD interest if I withdraw early?

Withdrawing funds before a CD matures usually triggers an Early Withdrawal Penalty (EWP). This penalty is typically calculated as a set number of days or months of interest (e.g., 90 days of interest). If you haven't earned enough interest to cover the fee, the bank may deduct the difference from your principal balance.

Current CD Special Rates

Take advantage of our competitive Certificate of Deposit rates. Ready to grow your savings? Open a CD online.

Choose Your Term CD Special

3.55%

9 to 18 Months APY^†

How Much Could Your Savings Grow?

See how much your savings can grow with a Certificate of Deposit. Enter your details below to calculate your potential earnings at maturity.

Initial Deposit

Over a period of

APY

Balance after maturity

Details
Initial deposit	-
CD term	-
APY	-
Interest earned	-

Disclaimer: This calculator provides estimates only and is not a guarantee of actual earnings. Annual Percentage Yield (APY) subject to change without notice. Minimum deposit of $1,000.00 required. Existing CD renewals not subject to the special rates at maturity unless specifically requested at maturity. Interest is compounded and paid quarterly. Fees may reduce earnings. Penalty for early withdrawal may apply including loss of principal. Please contact us for current rates and complete details.

Frequently Asked Questions About CDs

Have questions about calculating the growth of your Certificates of Deposit? We've compiled answers to the most common questions to help you make informed decisions about your savings.

How is CD interest calculated?

CD interest is calculated using the compound interest formula, which determines your final balance based on the principal, interest rate, and how often interest is added to the account.

The compound interest formula is:

A = P ( 1 + rn) nt

A: The final amount (maturity value).
P: The principal (initial deposit).
r: The annual interest rate (decimal).
n: The number of times interest compounds per year.
t: The number of years the money is invested.

For a simple daily interest calculation (often used for short-term CDs), banks may also use: Interest = (Principal × Rate) ÷ 365 × Days in Term

What is APY on a CD?

APY (Annual Percentage Yield) is the actual rate of return you earn on a CD in one year, accounting for the effect of compound interest.

While the "interest rate" (nominal rate) tells you the base percentage, the APY tells you the "real" yield. Because you earn interest on your interest, the APY is almost always higher than the stated interest rate. It provides a standardized way to compare different CDs regardless of their compounding frequency.

Key Difference: The interest rate is the "sticker price," while the APY is the "actual earnings" after compounding is factored in.

How are CDs compounded at FSB?

At FSB, CD interest is typically compounded and credited quarterly. This means your earnings are calculated and added to your balance every three months (four times a year).

How it works:

The Schedule: Every quarter, the bank calculates interest based on your daily balance.
The Growth: That interest is added back into your CD, so in the next quarter, you earn interest on your original deposit plus the interest you just earned.
The Result: This quarterly "compounding" is what creates your APY (Annual Percentage Yield), which is slightly higher than your base interest rate.

What happens to CD interest if I withdraw early?

If you withdraw funds before the maturity date, you will typically face an Early Withdrawal Penalty (EWP). This penalty usually "eats" into your earned interest and, in some cases, your principal.

Common penalty structures include:

Fixed Interest Forfeiture: You lose a set amount of interest (e.g., "90 days of interest" or "6 months of interest").
Principal Reduction: If you haven't earned enough interest to cover the penalty, the bank will deduct the remaining balance from your initial deposit.
Full Interest Forfeiture: Some strict CDs may require you to forfeit all interest earned if you close the account early.

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CD Calculator Disclosures

^†All rates are subject to change without notice. Interest bearing account – refer to FSB rate sheet for information on Interest Rates and Annual Percentage Yields. Fees may reduce earnings. FSB is not responsible for typographical errors or omissions. Minimum deposit of $1,000.00 required. Existing CD renewals not subject to the special rates at maturity unless specifically requested at maturity. Interest is compounded and paid quarterly. Fees may reduce earnings. Penalty for early withdraw may apply including loss of principal. For current rate information call 319-377-4891. Rate = Interest Rate