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8 minutes read

How Does Credit Card Interest Work? Understanding Annual Percentage Rate (APR)

Learn how credit card interest works, minimize debt with smart Annual Percentage Rate (APR) management, and maximize your card benefits with our simple guide.

By Brian Flaherty, B.A. Economics

Edited by Rachel Lauren, B.A. in Business and Political Economy

Ever wondered how credit card interest works? With US credit card balances now at a record high of over $1 trillion, it's a topic that's causing quite a headache for many. In short, credit card interest is a fee charged for borrowing money, and it accumulates when cardholders carry a balance from month to month.

By understanding the inner workings of credit card interest, you can unlock your card's full potential and minimize, or even completely avoid, those pesky charges.

Key takeaways

  • Credit card interest is the cost of borrowing money on your credit card
  • It's calculated using an annual percentage rate (APR), which is applied to any balance carried into a new billing cycle
  • To avoid credit card interest, pay your statement balance in full each month, or as much as possible to minimize interest

    How does credit card interest work?

    Credit card interest works by applying an Annual Percentage Rate (APR) to the balance that isn't repaid at the end of each month. Basically, if you carry a balance into the next billing cycle, your credit card company will charge you interest.

    What's the difference between interest and APR?

    When you sign up for a credit card, you'll see an interest rate. This is essentially the cost of borrowing money, charged if you're unable to pay off your balance before your next billing period starts. In credit card terms, this interest is usually expressed as a yearly rate, better known as the Annual Percentage Rate or APR.

    Contrary to what you might think, the APR isn't charged annually. Instead, credit card interest compounds on a daily basis, meaning credit card companies use this rate to calculate your daily interest, and your bill is due each month.

    However, this interest isn’t charged unless the balance carries over to the next month. If you're carrying a balance each month, understanding your APR is crucial to reduce the cost.

    How do you calculate credit card interest?

    To estimate your interest charges, you'll need 3 bits of info:

    1. Your average daily balance
    2. Days in your billing cycle
    3. Your APR

    Let's use an example. Say you have a travel rewards card with an average daily balance of $1,500 for a 30-day billing cycle, and your APR is 15.99%.

    Here's what you do:

    1. Divide your APR by the number of days in a year (0.1599 / 365 = 0.00044 daily periodic rate).
    2. Add 1 to this daily rate and raise it to the number of days in your billing cycle ([1 + 0.00044] ^ 30 = 1,519.93).
    3. Subtract this number by your average daily balance (1,519.93 - 1,500 = $19.93).

    So, for this billing cycle, you'd get a charge of around $19.93 in interest. To get a completely accurate calculation, don’t round any of the numbers. You’ll probably need a spreadsheet to help you out!

    Though it needs some back-of-the-napkin calculations, the principle is simple - carry a balance, and you'll pay interest.

    How can you avoid or minimize credit card interest?

    Avoiding interest completely is ideal, but if that's not possible, minimizing it is the next best thing. Here are a few strategies you can use:

    • Pay off your balance in full each month: Pay attention to 3 numbers on your credit card: total balance (what you owe overall), statement balance (what you spent in the last billing cycle), and minimum payment (the smallest amount to stay in good standing). You get a grace period, usually 21 days, to pay off the statement balance and avoid interest on new purchases. To dodge all interest charges, pay off the total outstanding balance.
    • Pay more than the minimum: If clearing the entire balance isn't possible, try covering as much as you can to avoid late fees and reduce the balance that’s subject to interest. The minimum payment is generally about 3% of the outstanding total, but covering more will help lower those interest charges. But beware, only paying the minimum will have you paying off your credit cards for a long time.

    Do all credit cards have a grace period?

    Unfortunately, no. Credit card issuers aren't required to give you a grace period. But there's a silver lining - many still do. And if they do offer a grace period, they're required to send you a bill at least 21 days before your due date.

    What are the different types of interest and APR?

    Your credit card's APR is either fixed (generally unchanged, unless your payment is more than 60 days late or when a promotional offer ends) or variable, shifting with the prime rate, often starting with the prime rate before adding a margin.

    Credit cards may feature several types of APR:

    • Purchase APR: Applies to purchases made with the card.
    • Balance Transfer APR: Applies to debts transferred from one credit card to another.
    • Cash Advance APR: Applies to cash borrowed using your card, usually higher, and typically doesn't have a grace period. The Consumer Financial Protection Bureau warns that interest generally starts accruing from the date of the transaction. Cash advances should really only be used as a last resort when you’re short on cash.
    • Introductory APR: A temporary promotional APR is offered to convince you to sign up. It can apply to purchases and/or balance transfers for a limited time, often lower than the regular APR, and sometimes even 0%. Be careful though - these don't last forever. And if you're over 60 days late, you may face a penalty APR.
    • Penalty APR: Charged when you make late payments or break the card's terms and conditions. This is typically the highest APR, and it kicks in if you're over 60 days late.

    When it comes to handling credit card interest, a little knowledge and caution can go a long way. By making smart choices and steering clear of pitfalls, you can handle credit card usage without the burden of scary interest charges. Below is a useful table to guide you on what you should and shouldn't do:


    • Understand your APR

    • Pay bills on time

    • Use grace periods

    • Opt for low-interest cards if needed


    • Carry a balance

    • Make just the minimum payment

    • Ignore the fine print

    • Forget about cash advance APR

    Advantages and disadvantages of credit card interest

    Despite the potential cost, credit card interest isn't all bad. In fact, if you understand the system and play by the rules, you can turn it to your advantage. However, it's important to weigh the pros and cons when it comes to credit card interest.

    Advantages of credit card interest

    • Enabling purchases you can't immediately afford: credit cards allow you to buy now and pay later, giving you financial flexibility.
    • Opportunity to build credit score: When used responsibly, credit cards can help improve your credit score, opening the door to better financial products and rates.

    Disadvantages of credit card interest

    • Potentially steep interest charges: If you carry a balance from month to month, the interest can add up quickly.
    • Risk of accumulating debt: High-interest charges can easily tumble into overwhelming debt if not properly managed.
    • Possible impact on your credit score: Late or missed payments can harm your credit score, making it harder to secure credit in the future.

    TuitionHero, your ally in college finance

    At TuitionHero, we understand that finances can be stressful. Whether it's student loans, scholarships, or understanding your credit card's APR, knowing how to navigate these areas is crucial. That's why we're committed to simplifying these financial topics and empowering you with the knowledge you need.

    As we've seen in this blog post, understanding how to manage credit card interest is key to mastering your finances. At TuitionHero, our services are designed to help you take control of your finances and maximize your benefits.

    Whether you're a student or a parent, we're here to guide you to financial success. Our credit card offers and educational resources can help you understand and handle credit card interest effectively.

    Final thoughts

    Understanding and managing credit card interest is a huge aspect of personal finance. By grasping your card's APR and how it translates into monthly charges, you can keep debt under control and make the most out of your card's benefits. We hope this information empowers you to steer clear of unnecessary costs and find financial success.

    Remember, TuitionHero is always here to support you on your path to financial success. For more help on private student loans, scholarships, or more about credit cards, explore our helpful resources on our TuitionHero webpage.

    Frequently asked questions (FAQ)

    Credit card interest is calculated using your card's annual percentage rate (APR), your average daily balance, and the number of days in your billing cycle. Most credit card companies use an average daily balance method to compute your charges. For a detailed breakdown, visit our credit card offers page.

    Yes, by paying off your statement balance in full each month, you can avoid paying credit card interest. Additionally, taking advantage of your credit card's grace period, typically 21 days from the purchase date to the payment due date, can help you avoid interest charges on new purchases.

    Yes, your credit score is a big factor in determining your APR. Cardholders with excellent credit scores often receive lower rates, while those with lesser scores may be subject to higher interest rates. Understanding credit scores and improving yours can lead to better rate offers.

    Not all cards provide a grace period. If they do, the issuer must ensure the bill is mailed or delivered at least 21 days before the due date. For more information about this, check out our credit card offers section.



    Brian Flaherty avatar

    Brian is a graduate of the University of Virginia where he earned a B.A. in Economics. After graduation, Brian spent four years working working at a wealth management firm advising high-net-worth investors and institutions. During his time there, he passed the rigorous Series 65 exam and rose to a high-level strategy position.


    Rachel Lauren avatar

    Rachel Lauren is the co-founder and COO of Debbie, a tech startup that offers an app to help people pay off their credit card debt for good through rewards and behavioral psychology. She was previously a venture capital investor at BDMI, as well as an equity research analyst at Credit Suisse.

    At TuitionHero, we're not just passionate about our work - we take immense pride in it. Our dedicated team of writers diligently follows strict editorial standards, ensuring that every piece of content we publish is accurate, current, and highly valuable. We don't just strive for quality; we aim for excellence.

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