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How Does Credit Card Interest Work?

Last Updated: November 21, 2024
7 min read

Table of contents

Key points:

  1. Credit card interest is a fee a card issuer charges if you carry a balance past your credit card bill due date.

  2. You may not be charged interest on purchases if you pay your statement balance in full by the due date and don't take a cash advance or balance transfer.

  3. Credit score is one factor used to determine interest rates for credit cards.

If you use credit cards, you’ve likely encountered an interest charge on one or more of your monthly credit card statements. But how does interest on credit cards work?

 

Understanding a few facts about credit card interest can help you manage your borrowing and could even minimize your chance of being charged interest. Here’s what you need to know about credit cards and interest rates.

What's your credit card interest rate?

Your credit card transactions are subject to an interest rate, also called your annual percentage rate (APR). Most credit card issuers charge a variable APR that can fluctuate, with the ability to increase or decrease over time. While your APR is an annual rate, some credit card issuers compound interest daily and use your APR to calculate your daily interest rate.

Credit card interest can be considered the cost of borrowing money—specifically, the fee your credit card issuer (or credit card company) charges you for carrying a balance after the billing period ends.

Your credit issuer usually determines the interest rate you'll receive when you apply for a credit card. There are many factors that can influence what interest rate your credit card issuer offers you, like your credit report, credit score, and the type of card you apply for. It’s a good practice to review your credit score periodically to ensure accuracy and to prepare for the future.

Can credit cards have more than one interest rate?

Credit cards can have multiple interest rates. The most common is the purchase APR, also called the standard interest rate, which applies to the purchases you make with the card.

A different interest rate often applies to a cash advance, which is typically higher than your standard credit card interest rate. And in some cases when you transfer a balance from one credit card to another, your balance transfer APR may differ from your purchase APR.

A credit card company may also impose a higher penalty APR if a cardmember fails to make their minimum monthly payment or pays late.

Different types of interest rates

In addition to having different interest rates for different transaction types, credit cards may also have variable or fixed interest rates.

 

Typically speaking, credit cards charge a variable interest rate, which means the rate can vary depending on the market. Some credit card companies may offer fixed interest rates, meaning it won’t fluctuate with the market, but these kinds of cards are more rare.

How is credit card interest calculated?

Credit card charges are subject to daily interest if you carry a credit card balance past your monthly payment due date or take out a cash advance. Daily credit card interest could also accrue on a balance transfer credit card offer, so review the terms and conditions before you apply.  

Let's look at how card issuers calculate credit card interest.

At the end of each day, your credit card issuer multiplies your outstanding balance by your daily rate to generate your daily interest charge. Those credit card interest charges get added to your credit card balance the next day through a process called compounding. To determine how much interest you’ll pay on your balance each day, you can convert your APR to a daily percentage rate by dividing your APR by 365 (days in a year). 

For example: If your credit card APR is 15%, your daily rate is 0.041096%. Let’s say you carry a $1,000 balance from your previous billing cycle (or billing period); you can multiply that balance by your daily rate to arrive at the daily interest you’ll pay for the first day. In this case, your daily charge would bring your next day’s balance to $1,000.41 (plus any additional purchases and minus any new credits or payments). This process occurs each day until the end of your monthly billing cycle. Let’s say you made no other purchases or payments that month, and it’s a 30-day billing period. Your beginning $1,000 balance would become $1,012.40 on the last day of your billing cycle.

You can use the Discover credit card interest calculator to find the total you’d pay in interest based on your balance, interest rate, and monthly minimum payment. You can also see how adjusting your monthly payments could shorten your payoff time.

When does interest start to accrue on a credit card?

The day interest starts to accrue on your credit card transactions depends on a few factors, including the type of transaction. 

By paying your balance in full every month, you could avoid being charged interest on credit cards or losing your grace period, according to the Consumer Financial Protection Bureau. A grace period is typically from the day a charge posts to the payment due date on your following credit card statement.

If you carry a portion of your statement balance into the next month, you could lose the grace period that kept you from incurring interest charges. Along with the balance you carried over, all new charges could begin accruing interest from the day they're posted to your account. In other words, any purchases you make during a billing cycle are subject to interest charges if you don’t pay them off by the payment due date on that month’s billing statement. Any interest you accrue appears on your following billing statement.

Unlike regular purchases, a cash advance (borrowing cash from your credit limit) can typically start accruing a higher interest the day it posts to your account. Cash advances may also cause you to lose your grace period on purchases since you'll likely receive an interest charge.

A balance transfer (transferring credit card debt from one card to another) may be subject to daily interest the day it posts, which could cause you to lose your grace period. However, some credit card companies offer a promotional 0% APR on balance transfers and purchases. So, if you pay your credit card debt (balance transfer and purchases) off before the promotional period ends, you won’t pay interest charges or lose your grace period. Remember that your promotional interest rate could return to the standard rate once the introductory period expires, and the standard rate may apply to any unpaid balance and future transactions.

If you might carry a balance from month to month, the best credit card for you could be a balance transfer card with a low interest rate after the introductory period ends or a lower interest rate than the other credit card options you may have available. Plus, a balance transfer card that offers rewards could be an added benefit.

Did you know?

With a Discover it® credit card you can earn 5% cash back on everyday purchases at different places you shop each quarter, up to the quarterly maximum when you activate.

Knowing how credit card interest rates work can inform your borrowing decisions and help empower your financial future. To understand the interest rates you’ll pay, check the terms and conditions when applying for a new credit card or managing an existing one.

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