Calculate APY
What is APY?
APY, or Annual Percentage Yield, is the rate of return on an investment or savings account over a year, taking into account the effect of compounding interest. It provides a more accurate picture of the actual earnings compared to the nominal interest rate. For financial definitions and examples, see Investopedia's APY definition. Explore our Tools page to compare APY with other finance calculators like profit and discount tools.
APY is calculated using the formula: APY = (1 + r/n)^n - 1, where r is the nominal interest rate and n is the number of compounding periods per year.
How APY Calculation Works
The APY formula accounts for compounding, which means interest is earned on both the initial principal and the accumulated interest from previous periods. This is why APY is always slightly higher than the nominal rate for compounding frequencies greater than once per year.
For example, if you have a nominal rate of 5% compounded monthly (12 times per year), the APY would be calculated as:
APY = (1 + 0.05/12)^12 - 1 = 5.116%
APY vs APR
While APY measures the total return on an investment, APR (Annual Percentage Rate) represents the cost of borrowing. APY is typically used for savings and investments, while APR is used for loans and credit cards.
| Aspect | APY | APR | |
|---|---|---|---|
| Focus | Earnings on investments | Cost of borrowing | |
| Compounding | Includes compounding | May or may not include | |
| Typical Use | Savings accounts, CDs | Loans, credit cards |
| Compounding Frequency | Periods per Year | APY Effect | Example (5% Nominal) |
|---|---|---|---|
| Annually | 1 | Lowest growth | 5.00% APY |
| Semi-annually | 2 | Moderate increase | 5.06% APY |
| Quarterly | 4 | Further increase | 5.09% APY |
| Monthly | 12 | Significant growth | 5.12% APY |
| Daily | 365 | Maximum growth | 5.13% APY |
Examples
Example 1: A savings account with a 4% nominal rate compounded quarterly (4 times per year).
APY = (1 + 0.04/4)^4 - 1 = 4.06%
Example 2: An investment with a 6% nominal rate compounded daily (365 times per year).
APY = (1 + 0.06/365)^365 - 1 ≈ 6.18%
FAQ
What is the difference between APY and nominal interest rate?
The nominal rate is the stated rate without considering compounding, while APY reflects the actual annual return including compounding effects.
Why is APY important for investors?
APY helps investors compare different investment options by showing the true annual return, making it easier to choose the best option.
Can APY be lower than the nominal rate?
No, APY is always equal to or higher than the nominal rate due to the compounding effect.
How often should I calculate APY?
Calculate APY whenever you're comparing investment options or when interest rates change.
Learn More
For more information on APY and compounding interest, visit Investopedia or Consumer Financial Protection Bureau.