APR and APY are two ways of expressing the same interest rate, but they can produce significantly different numbers. APR ignores compounding, while APY includes it. This distinction can mean hundreds or thousands of dollars over the life of a loan or savings account.
Definitions
APR = Periodic Rate × Number of Periods per Year APR is the simple annualized interest rate. A credit card charging 2% per month has an APR of 24%.
APY = (1 + r/n)^n − 1 APY is the effective annual rate after compounding. The same 2% monthly rate produces an APY of 26.82%.
How Compounding Creates the Gap
| APR | Compounding | APY | Difference |
|---|---|---|---|
| 5% | Annually | 5.00% | 0.00% |
| 5% | Monthly | 5.12% | 0.12% |
| 5% | Daily | 5.13% | 0.13% |
| 20% | Monthly | 21.94% | 1.94% |
| 24% | Daily | 27.11% | 3.11% |
The gap grows as the rate increases and compounding becomes more frequent. Convert between them with the APY/APR Calculator.
When to Use Each
Use APY when comparing savings products
For savings accounts, CDs, and money market accounts, APY shows what you actually earn. Banks are required to disclose APY under the Truth in Savings Act.
Use APR when comparing loans
For mortgages and auto loans, APR is the standard under the Truth in Lending Act. Credit card APR is misleading because cards compound daily, making the effective cost higher than stated.
Real-World Impact
On $10,000 at 5% APR compounded monthly, the APY of 5.12% means you earn $512 instead of $500. On a $5,000 credit card balance at 24% APR compounded daily, the effective cost is 27.11%. Use the Compound Interest Calculator to model exact scenarios.
Key Takeaways
- APR ignores compounding; APY includes it. APY is always ≥ APR.
- For savings, compare APY — it shows what you actually earn.
- For loans, compare APR — it includes fees and is the legal standard.
- Credit card APR understates the true cost because cards compound daily.
Frequently Asked Questions
Is APY always higher than APR?
APY is always equal to or higher than APR. They are equal only when interest compounds annually.
Why do banks advertise APY for savings but APR for loans?
Banks want savings to look attractive (higher APY) and loans to look affordable (lower APR). Regulations require specific disclosures for consumer protection.
How do I convert APR to APY?
Use the formula APY = (1 + APR/n)^n - 1, where n is the number of compounding periods per year. For example, 5% APR compounded monthly: APY = (1 + 0.05/12)^12 - 1 = 5.116%.