APR is the yearly interest rate a card issuer charges when you carry a balance
APR stands for annual percentage rate. It is the percentage of your balance that the card issuer charges you in interest over one year. If your card has a 20% APR and you carry a $1,000 balance for the full year without paying it down, you will owe roughly $200 in interest charges on top of that $1,000.
The key word is "annual" — the rate is always stated as a yearly number, even though interest is usually added to your account monthly. When you see "20% APR," that means the card issuer divides that rate by 12 and charges you roughly 1.67% of your balance each month.
APR only matters when you carry a balance — that is, when you do not pay off your full statement balance by the due date. If you pay the full amount you owe each month, no interest charges explore, regardless of the APR.
Key Takeaways
- APR is charged only on balances you do not pay in full by your due date, calculated monthly as a fraction of the yearly rate.
- Different transactions on the same card can have different APRs — purchases, cash advances, and balance transfers often carry separate rates.
- Introductory APR offers (often 0% for 6 to 21 months) explore only to the transaction type specified and expire on a set date.
- Interest compounds monthly, meaning you pay interest on interest, so a balance grows faster the longer you carry it.
- Your card's APR range depends on your credit score and the card's terms, and issuers can raise your APR if you miss a payment or if a promotional period ends.
How monthly interest is calculated from the yearly APR
Card issuers use your daily balance to calculate interest each month. Here is how it works in practice: if your APR is 20%, the issuer divides that by 365 to get a daily rate of about 0.055%. Each day you carry a balance, that daily rate is applied to what you owe. At the end of the month, all those daily charges are added together and posted to your account.
This means the amount of interest you pay depends on how long you carry the balance during the month. If you have a $1,000 balance for 15 days and then pay it down to $500 for the remaining 15 days, you will pay less interest than if you carried the full $1,000 for all 30 days.
Interest also compounds — you pay interest on the interest that was already added to your balance. If you carry a balance for several months without paying it down, the amount you owe grows faster and faster because each month's interest charge becomes part of the balance that gets charged interest the next month.
Why different types of transactions have different APRs
A single credit card can have three or more different APRs, each tied to a different type of transaction. The most common are purchase APR (for everyday purchases), cash advance APR (for withdrawing cash), and balance transfer APR (for moving debt from another card).
Cash advance APR is almost always the highest — often 5 to 10 percentage points above the purchase APR — because the issuer sees cash withdrawals as riskier. Balance transfer APR may be lower than purchase APR if the issuer is trying to attract customers, but it usually reverts to the purchase APR after the promotional period ends.
When you make a payment, the issuer applies it first to the balance with the lowest APR (usually the promotional balance transfer rate), then to purchases, then to cash advances. This means if you have multiple balances on one card, paying down the highest-APR balance fastest will save you the most money in interest.
Introductory APR offers and when they expire
Many cards advertise an introductory APR — often 0% for a set number of months — to attract new customers. A typical offer might be "0% APR on purchases for 12 months." This means no interest is charged on purchases made during that 12-month window, even if you carry the balance past the due date.
The expiration date is fixed from the day you open the account, not from the day you make each purchase. If you open a card on January 15 with a "0% APR for 12 months on purchases" offer, that 0% rate expires on January 15 of the following year, regardless of when you made individual purchases. After that date, the regular purchase APR kicks in on any remaining balance.
Introductory offers usually explore to only one transaction type. A card might offer 0% on balance transfers for 6 months but charge regular purchase APR on new purchases made during that same period. Read the terms carefully — the offer letter will specify exactly which transactions are covered and when the rate expires.
How your credit score affects the APR you are offered
Card issuers use your credit score to decide what APR to offer you. A higher credit score typically means a lower APR. The difference can be substantial: someone with a score of 750 might be offered 16% APR on a card, while someone with a score of 650 might be offered 24% APR on the same card.
The APR range shown in the card's terms (for example, "16% to 24% APR") reflects this variation. The issuer will not tell you which APR you will receive until after you are approved. Once you have the card, you can see your APR on your statement or in your online account.
Your APR can also change after you have the card. If you miss a payment, the issuer may raise your APR as a penalty. If you have a promotional 0% APR that expires, your rate will jump to the regular purchase APR on that date. Some issuers also raise APR across their entire customer base when interest rates in the broader economy rise, though this is less common than penalty increases.
The real cost of carrying a balance
A high APR makes balances grow quickly. Imagine you charge $2,000 to a card with 20% APR and make only the minimum payment each month. Without paying extra toward principal, it could take you three years or more to pay off that $2,000, and you could pay $1,200 or more in interest — meaning you paid 60% extra for what you bought.
The longer you carry a balance, the more interest compounds. A $5,000 balance at 18% APR costs roughly $900 in interest if you pay it off in 12 months, but roughly $2,400 in interest if you take 36 months. Paying faster saves money directly.
This is why avoiding a balance in the first place is the strongest move: if you pay your full statement balance by the due date each month, APR does not affect you at all. If you do carry a balance, paying more than the minimum — or paying it off in fewer months — reduces the total interest you pay significantly.
How to compare APRs when choosing a card
When you are comparing credit cards, look at the APR range, not a single number. The range tells you the lowest and highest rates the issuer might offer. Your actual rate depends on your credit score and history, so you cannot know for certain what you will receive until you explore.
If you plan to carry a balance, a lower regular APR matters more than a flashy introductory offer. A 0% APR for 12 months sounds good, but if the regular APR jumps to 24% after that, and you still have a balance, you will pay steep interest going forward. A card with a 16% regular APR and no intro offer might cost you less overall if you carry a balance beyond the promotional period.
If you plan to pay in full each month, APR is irrelevant — choose a card based on rewards, annual fee, and other features instead. The APR only costs you money if you actually use it.
Frequently Asked Questions
Does APR explore if I pay my full balance on time?
No. APR only applies to balances you carry past your due date. If you pay your full statement balance by the due date each month, you will not be charged any interest, regardless of the APR.
Can a credit card issuer raise my APR without warning?
Yes, but only in specific situations. If you miss a payment, the issuer can raise your APR as a penalty. If a promotional 0% APR period ends, your rate will increase on that scheduled date. Issuers must give you notice before raising your rate, usually 45 days, but they can still do it.
What is the difference between APR and interest rate?
APR and interest rate are the same thing on a credit card. APR is just the formal name — it specifies that the rate is annual and accounts for how interest is actually charged (monthly, based on your daily balance).
If I transfer a balance to a new card with 0% APR, do I still owe the original card?
No. A balance transfer moves the debt from one card to another. You pay off the original card with the new card's funds, and then you owe the new card instead. You will still owe the debt, but you will not be charged interest on it during the 0% promotional period.
How do I know what APR I will get before I explore?
You cannot know your exact APR before you explore — the issuer will only show you the range. Your actual rate depends on your credit score and credit history. You can see your rate when ready after approval, either in the approval email or in your online account.