FinanceFirst financial glossary
What is Annual Percentage Yield (APY)?
A direct definition, followed by examples, comparisons, related concepts, and the sources that support the explanation.
Written by Asim Ahmad, Founder and Editor, FinanceFirst
Definition
In one sentence about Annual Percentage Yield (APY)
Annual Percentage Yield (APY) is the effective annual rate of return on a savings account or investment, accounting for the effect of compound interest. APY reflects how much you actually earn over one year, including interest earned on previously accumulated interest. It is always equal to or higher than the stated interest rate.
Why APY Matters
APY is the most accurate way to compare savings products because it accounts for compounding frequency. Two savings accounts could both advertise a 4.50% interest rate, but if one compounds daily and the other compounds annually, the daily-compounding account actually earns more. The APY standardizes this comparison. The Truth in Savings Act requires all banks to disclose APY, making it easy for consumers to compare offers and choose the account that earns the most.
Real-World Example: How Compounding Frequency Affects APY
Here is how the same 4.50% stated interest rate produces different APYs based on compounding frequency, using a $10,000 deposit:
| Compounding Frequency | APY | Interest Earned (1 Year) | Difference from Annual |
|---|---|---|---|
| Annually | 4.500% | $450.00 | $0.00 |
| Quarterly | 4.577% | $457.71 | $7.71 |
| Monthly | 4.594% | $459.37 | $9.37 |
| Daily | 4.603% | $460.25 | $10.25 |
APY Formula
APY = (1 + r/n)^n - 1, where r is the stated annual interest rate (as a decimal) and n is the number of compounding periods per year. For example, with a 4.50% interest rate compounded daily: APY = (1 + 0.045/365)^365 - 1 = 4.603%. This means a $10,000 deposit earns $460.25 over one year, not just $450.00.
When APY Applies
APY is used whenever you are earning interest:
- Savings accounts: Compare APY across banks to maximize your earnings
- High-yield savings accounts: Online banks typically offer APYs 10-25x higher than traditional banks
- Certificates of Deposit (CDs): APY on CDs is fixed for the term, allowing you to lock in a rate
- Money market accounts: Similar to savings but may include check-writing privileges
- Interest-bearing checking accounts: Some checking accounts offer modest APY on balances
Common APY Mistakes
These errors can lead to poor savings account choices:
- Confusing APY with APR: APY is for savings (what you earn), APR is for loans (what you pay). They are calculated differently and serve opposite purposes
- Comparing interest rates instead of APY: Always use APY for apples-to-apples comparison of savings products
- Ignoring promotional vs. ongoing APY: Some banks offer a high introductory APY that drops after a few months. Read the fine print
- Assuming APY is guaranteed: HYSA rates are variable and change with Federal Reserve policy. Only CDs lock in a fixed APY for the full term
- Not accounting for taxes: Interest income is taxable. At a 22% tax bracket, a 4.50% APY yields an after-tax return of about 3.51%
Side-by-side
APY vs. APR: Key Differences
| Feature | APY (Annual Percentage Yield) | APR (Annual Percentage Rate) |
|---|---|---|
| Used for | Savings, deposits, earnings | Loans, credit cards, borrowing |
| Includes compounding? | Yes | No |
| Higher number is... | Better for you | Worse for you |
| Required disclosure | Truth in Savings Act | Truth in Lending Act |
Key distinction: When saving: look for the highest APY. When borrowing: look for the lowest APR.
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Common questions
Frequently asked questions
What is a good APY for a savings account in 2025?
As of early 2025, competitive HYSAs offer APYs between 4.00% and 5.00%. Anything above 4.00% is good. The national average for traditional savings accounts is just 0.01%. If your current account offers less than 1.00% APY, you are likely losing purchasing power to inflation.
Is APY the same as interest rate?
No. The interest rate is the base rate before accounting for compounding. APY includes the effect of compounding, so it is always equal to or higher than the stated interest rate. For daily compounding, a 4.50% interest rate produces a 4.60% APY.
How is APY taxed?
Interest earned through APY is taxed as ordinary income at your marginal tax rate. Banks issue a 1099-INT form if you earn more than $10 in interest during the year. The tax applies to the total interest earned, regardless of whether you withdraw it.
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Sources and further reading
Use these links to check the underlying definition, rule, dataset, or consumer guidance. External pages can change after publication.