APY vs APR Calculator
Understanding APY and APR
In the world of finance, especially for savings accounts, certificates of deposit (CDs), loans, and credit cards, two key terms often surface: APY (Annual Percentage Yield) and APR (Annual Percentage Rate). While both represent interest rates, they tell different stories about the cost or earning potential of a financial product. Understanding the distinction is crucial for making informed financial decisions.
What is APR (Annual Percentage Rate)?
The APR represents the total cost of borrowing or the total interest earned on an investment over one year, expressed as a percentage. It includes not only the simple interest rate but also any additional fees or charges associated with a loan or credit product (like origination fees, discount points, or mortgage insurance premiums). For savings accounts or investments, APR typically refers to the nominal interest rate, which is the stated interest rate without considering the effect of compounding.
Formula for Nominal Rate (APR): The input for the nominal interest rate is usually the stated rate itself.
What is APY (Annual Percentage Yield)?
The APY, on the other hand, is a more comprehensive measure of the return on an investment that accounts for the effect of compounding interest. Compounding means that the interest earned is added to the principal, and then the next interest calculation is based on the new, larger principal. This leads to a higher effective rate of return over time compared to simple interest. APY is particularly relevant for savings accounts, money market accounts, and CDs, where interest is typically compounded more than once a year.
The APY Formula:
APY = (1 + r/n)^n – 1
Where:
- r is the nominal annual interest rate (APR) expressed as a decimal.
- n is the number of compounding periods per year.
For example, if interest is compounded monthly, n = 12. If compounded quarterly, n = 4. If compounded daily, n = 365.
Key Differences and When to Use Each
- APR is generally used for loans and credit cards to show the total cost, including fees. It represents the simple interest rate before compounding.
- APY is used for savings accounts and investments to show the effective rate of return after compounding. It allows for a true comparison between different savings products.
When comparing savings accounts, always look at the APY. A higher APY means you will earn more interest over the year due to the power of compounding. When comparing loans, look at the APR, as it reflects the true cost of borrowing, including fees.
Calculator Usage
This calculator helps you determine the APY when you know the nominal interest rate (APR) and how often the interest is compounded annually.
- Enter the Nominal Interest Rate (APR) as a percentage (e.g., 5 for 5%).
- Enter the Number of Compounding Periods per Year (e.g., 1 for annually, 2 for semi-annually, 4 for quarterly, 12 for monthly, 365 for daily).
- Click "Calculate APY" to see the effective annual yield.
Example Calculation
Let's say you have a savings account with a nominal interest rate (APR) of 4.8%, and the interest is compounded monthly (12 times a year).
- Nominal Rate (r) = 4.8% or 0.048
- Compounding Periods (n) = 12
Using the formula: APY = (1 + 0.048/12)^12 – 1
APY = (1 + 0.004)^12 – 1
APY = (1.004)^12 – 1
APY = 1.04907 – 1
APY = 0.04907 or 4.907%
This means your effective annual yield is approximately 4.907%, slightly higher than the stated nominal rate of 4.8% due to monthly compounding.