APY Calculator
Calculate effective Annual Percentage Yield (APY) from nominal interest rate APR and compounding frequency to find your true annual return on savings accounts, HYSAs, and bank CDs.
Calculate Effective APY & Interest Earned
Enter stated APR %, compounding frequency, deposit principal, and duration.
APY Calculation Output
Quick Summary
Our apy calculator annual percentage yield interest earned converts stated nominal interest rates (APR) into true Annual Percentage Yield (APY) metrics based on compounding frequency. By accounting for daily, monthly, or quarterly compounding, this calculator discloses exact interest dollar returns for bank savings accounts, high-yield savings accounts (HYSAs), and certificates of deposit (CDs).
How It Works: APY vs APR & Bank Disclosure Regulations
The difference between APR and APY is compounding:
1. **APR (Annual Percentage Rate):** The basic annual interest rate charged or paid without taking intra-year compounding into account.
2. **APY (Annual Percentage Yield):** The real effective annual return earned when interest is compounded and added back to the principal balance.
Under the US **Truth in Savings Act (TISA)**, financial institutions are legally required to state APY on savings products so consumers can easily compare bank yields regardless of compounding schedule.
Formula Explanation
Your Effective Annual Percentage Yield ($APY$) and total compound balance ($A$) are calculated as follows:
Step-by-Step Worked Example
Here is a detailed 5-step breakdown for a $10,000 Certificate of Deposit (CD) offering a 5.00% APR with monthly compounding ($n=12$) over 1 year:
- Step 1 (Calculate Periodic Rate): $r = 5.00\% \div 12 = 0.41667\% = 0.0041667$.
- Step 2 (Apply APY Formula): $(1 + 0.0041667)^{12} - 1 = (1.0041667)^{12} - 1 = 1.05116 - 1 = \mathbf{5.116\% \text{ APY}}$.
- Step 3 (Calculate Ending 1-Year Balance): $\$10,000 \times 1.05116 = \mathbf{\$10,511.62}$.
- Step 4 (Calculate Total Interest Earned): $\$10,511.62 - \$10,000 = \mathbf{\$511.62 \text{ interest earned}}$.
- Step 5 (Compute Compounding Boost vs Simple APR): Simple Interest $= \$10,000 \times 5\% = \$500.00$. Monthly compounding provides a **$11.62 compounding boost**!
Calculation Examples: Real-World Scenario Comparison
Compare APY rates and interest earned on a $10,000 deposit over 1 year across compounding frequencies:
| Stated Nominal Rate (APR) | Compounding Frequency | Effective APY Yield | Total Interest Earned ($10k Deposit) | Compounding Boost |
|---|---|---|---|---|
| 4.50% APR | Monthly (12x/yr) | 4.594% APY | $459.40 | +$9.40 vs APR |
| 5.00% APR | Monthly (12x/yr) | 5.116% APY | $511.62 | +$11.62 vs APR |
| 5.00% APR | Daily (365x/yr) | 5.127% APY | $512.67 | +$12.67 vs APR |
| 5.50% High-Yield CD | Daily (365x/yr) | 5.654% APY | $565.36 | +$15.36 vs APR! |
Benefits of Using the APY Calculator
Utilizing this calculator provides essential bank comparison and yield transparency:
- Standardizes Savings Offer Comparisons: Allows fair side-by-side comparison between banks using different compounding periods.
- Discloses True Dollar Returns: Calculates exact dollar interest payments on CDs, money market funds, and HYSAs.
- Uncovers Hidden Compounding Value: Shows how daily compounding outpaces monthly or annual compounding.
- Prevents Misleading Financial Marketing: Ensures you evaluate actual yield rather than teaser APR interest rates.
Frequently Asked Questions (FAQ)
What is APY (Annual Percentage Yield)?
APY is the total percentage rate of interest earned on an investment or savings account in one year, taking into account the effects of interest compounding.
How does APY differ from APR?
APR is the stated simple interest rate per year without compounding. APY includes intra-year compounding, resulting in a higher effective return.
Why is APY higher than APR?
Because interest earned in early periods is added to the principal, causing subsequent interest to be earned on interest.
Is APY guaranteed on High-Yield Savings Accounts?
No. APY rates on HYSAs are variable and fluctuate with Federal Reserve interest rate policy changes. Certificate of Deposit (CD) APYs are fixed for the CD term.
How do banks calculate daily APY?
Daily APY uses the formula APY = (1 + APR / 365)^365 - 1.
What is a good APY for a savings account in 2026?
Competitive online high-yield savings accounts (HYSAs) typically offer 4.0% to 5.25% APY, compared to traditional brick-and-mortar bank national averages of 0.45% APY.
Are APY interest earnings subject to income tax?
Yes. Bank interest earnings over $10 per year are reported on IRS Form 1099-INT and taxed as ordinary income.
Can APY be negative?
Nominal APY cannot be negative, but Real APY (APY minus inflation rate) can be negative if inflation exceeds your bank yield.
How do CD early withdrawal penalties affect APY?
Withdrawing CD funds before maturity forfeits several months of interest, lowering your actual net effective APY.
What is the Truth in Savings Act APY requirement?
Federal law requires US banks to disclose APY on consumer savings accounts to provide transparent, standardized comparison metrics.