CD APY Calculator

Convert a stated interest rate (APR) into the actual annual percentage yield (APY) based on compounding frequency. Compare how different compounding schedules change the effective return on your CD.

Your CD Earnings

Final Balance $10,511.62

Total Interest Earned $511.62

Initial Deposit: $10,000.00
Annual Percentage Yield (APY): 5.00%
CD Term: 12 months
Compounding Frequency: Monthly

What Is a CD APY Calculator?

A CD APY calculator converts a nominal annual interest rate — often called the annual percentage rate (APR) — into the annual percentage yield (APY), which reflects the true return after compounding. Banks advertise both APR and APY, and the gap between the two numbers depends entirely on how often interest compounds. This calculator bridges that gap so you can compare CD offers from different institutions on equal terms.

Rate & Frequency

Deposit Amount
APY Rate
Term Length
Compounding

APY Converter A = P × (1 + r/n)^n×t

Effective Yield

Interest Earned
Final Balance
Growth Chart

Key Benefits of Using a CD Calculator

Convert any quoted APR into its equivalent APY to see the actual yearly return after compounding
Compare CD offers from different banks and credit unions when one quotes APR and another quotes APY
See how much extra yield daily compounding adds compared to monthly, quarterly, or annual compounding at the same stated rate
Verify that the APY listed on a CD disclosure matches the stated nominal rate and compounding schedule

CD APY Conversion Formula

The APY formula converts a stated nominal rate into the effective annual yield by accounting for the number of compounding periods within a year. The more frequently interest compounds, the higher the APY relative to the nominal rate.

A = P × ( 1 + r / n ) ^{n × t}

Click or tap any variable to see what it means

APY Annual Percentage Yield: The effective annual return after compounding. This is the true rate of return on a CD over one full year. APY is always equal to or greater than the nominal rate.
r Nominal Annual Rate (APR): The stated interest rate before compounding is applied. Banks sometimes advertise this rate alongside the APY. A 5.00% nominal rate compounded monthly produces a 5.116% APY.
n Compounding Periods Per Year: The number of times interest is added to the balance each year. Common frequencies: daily (365), monthly (12), quarterly (4), semi-annually (2), annually (1).

When compounding is annual (n = 1), APY equals the nominal rate exactly. As the number of compounding periods increases, APY rises above the nominal rate. The difference is most noticeable at higher interest rates.

How to Use the CD APY Calculator

Convert a CD's stated rate into the annual percentage yield in 3 steps. Use the result to compare offers from different banks on a level playing field.

Enter the Stated Interest Rate

Type the nominal annual rate (APR) from the CD offer. This is the rate before compounding adjustments. Enter 5.00 for a 5.00% stated rate.

Select the Compounding Frequency

Choose how often the bank compounds interest on the CD — daily, monthly, quarterly, semi-annually, or annually. This frequency is the key variable that determines the APY.

Read the Effective APY

The calculator displays the annual percentage yield (APY), the total interest earned on a sample deposit, and the final balance. Compare results across different compounding frequencies to see how each one affects your real return.

Factors That Affect CD APY

Three primary factors determine the annual percentage yield on a certificate of deposit. Understanding each factor helps you identify which CD offer gives the highest effective return.

Nominal Rate (APR)

The starting nominal rate sets the baseline. A higher nominal rate always produces a higher APY at any compounding frequency. A 5.50% nominal rate compounded monthly yields 5.641% APY, while a 5.00% nominal rate compounded daily yields only 5.127% APY.

Compounding Frequency

More compounding periods per year push the APY further above the nominal rate. At a 5.00% nominal rate, daily compounding yields 5.127% APY, monthly yields 5.116%, quarterly yields 5.095%, and annual yields exactly 5.000%.

Continuous vs. Discrete Compounding

Continuous compounding represents the mathematical upper limit of APY for a given nominal rate. At 5.00% nominal, continuous compounding yields 5.127% APY — essentially the same as daily compounding (5.127%). In practice, daily and continuous compounding produce nearly identical results.

Rate Disclosure Requirements

Federal regulations (Truth in Savings Act) require banks to disclose the APY on all CD products. The disclosed APY must reflect the actual compounding method the bank uses. Comparing APY figures directly is the most accurate way to evaluate competing CD offers.

APY Comparison: 5.00% Nominal Rate by Compounding Frequency

Daily365/yr

$2,840.25

Monthly12/yr

$2,833.59

Quarterly4/yr

$2,820.37

Annually1/yr

$2,762.82

Effective APY at a 5.00% nominal rate across compounding frequencies

CD APY Conversion Examples

These 4 examples show how the annual percentage yield (APY) changes based on the nominal rate and compounding frequency. Each example uses a $10,000 deposit over 1 year to illustrate the dollar impact of APY differences.

4.50% Nominal — Daily Compounding

Initial Deposit: $10,000
APY: 4.603%
Term: 1 Year
Compounding: Daily (365/yr)

Interest Earned $460.25

Final Balance $10,460.25

4.50% Nominal — Quarterly Compounding

Initial Deposit: $10,000
APY: 4.577%
Term: 1 Year
Compounding: Quarterly (4/yr)

Interest Earned $457.71

Final Balance $10,457.71