How.is Credit Card Interest Calculated

How Credit Card Interest Is Calculated

Credit card interest is typically calculated using the Annual Percentage Rate (APR), which represents the cost of borrowing over one year. The interest is calculated on the daily balance of your account, not just the amount you spend.

The interest is then added to your balance each day, and the process repeats. This means you're charged interest on interest, which is called compounding.

Key Terms

• APR (Annual Percentage Rate): The annual interest rate charged on your credit card balance.
• APY (Annual Percentage Yield): The effective annual interest rate, accounting for compounding.
• Grace Period: The time between when you make a purchase and when interest starts accruing (usually 21-25 days).
• Minimum Payment: The smallest amount you must pay each month to avoid penalties.

APR vs. APY

APR is the stated interest rate, while APY is the actual effective rate, including compounding. APY is always higher than APR because it accounts for the fact that you're earning interest on interest.

For example, if your credit card has a 20% APR, your APY would be approximately 21.9% if interest is compounded daily.

Interest Compounding

Compounding means that interest is added to your balance, and you earn interest on that new balance. This can lead to significantly higher interest charges over time.

To minimize interest, try to pay off your balance in full each month or use the calculator to estimate your interest charges.

Grace Periods and Interest Charges

Most credit cards offer a grace period (usually 21-25 days) during which no interest is charged. If you pay your balance in full during this period, you won't owe any interest.

If you don't pay your balance in full, interest will start accruing after the grace period ends. The interest will continue to accrue until you pay off the balance.

Late Payment Penalties

If you miss a payment, your credit card company may charge you a late fee. Some cards also increase your interest rate or impose other penalties.

To avoid penalties, set up automatic payments or reminders to pay your balance on time.

Example Calculation

Let's say you have a $500 balance on a credit card with a 20% APR and a 25-day grace period. If you don't pay your balance in full within the grace period, interest will start accruing.

Using the calculator on the right, you can estimate your interest charges for different scenarios. For example, if you leave the balance unpaid for 30 days, you'll owe approximately $509.50 in interest.