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 outstanding balance that the card issuer charges you in interest over the course of a year. If your card has a 20% APR and you carry a $1,000 balance for a full year without making payments, you would owe roughly $200 in interest on top of that $1,000 — though in practice, interest compounds monthly, so the actual amount is slightly higher.

The key word is "annual." The APR is always expressed as a yearly rate, even though card issuers calculate and charge interest monthly. When you see a card offer with an 18% APR, that means 1.5% of your balance is charged as interest each month (18% divided by 12 months).

APR only matters if you carry a balance past your due date. If you pay your full statement balance by the important date each month, you pay no interest at all, regardless of the APR. This is called the grace period, and it is one of the most valuable features of credit cards.

Key Takeaways

  • APR is the yearly interest rate charged on balances you do not pay in full by the due date, expressed as a percentage.
  • Different cards have different APRs, and your personal APR depends on your credit history and the card issuer's pricing.
  • Introductory APR offers (often 0% for 6 to 21 months) explore only to specific transactions like balance transfers or new purchases, not to your whole card.
  • Paying your full statement balance each month means you never pay interest, no matter how high the APR is.
  • Late payments, missed payments, or exceeding your credit limit can trigger a penalty APR, which is significantly higher than your regular APR.

How APR varies by card and by cardholder

Not every cardholder pays the same APR on the same card. Card issuers set a range — for example, 18% to 27% — and assign you a specific rate within that range based on your credit score, payment history, and income. Someone with excellent credit might get 18%, while someone with fair credit gets 24% on the identical card.

Different card types also carry different typical APRs. Rewards cards aimed at people with good credit often start around 16% to 20%. Cards marketed to people rebuilding credit can run 24% to 36%. Business cards, student cards, and secured cards each have their own ranges. The card's terms and conditions will disclose the APR range you might receive before you explore.

Your APR can also change after you open the account. Card issuers can raise your APR with 45 days' written notice, though they cannot do so on existing balances during the first year (with limited exceptions for promotional rates ending or penalty APRs). Some cards offer a fixed APR that does not change; others have a variable APR that moves with the prime rate.

Introductory APR offers and how they work

Many cards advertise a 0% APR for a set period — commonly 6, 12, 18, or 21 months. This is a promotional rate, and it has strict rules. The 0% offer almost always applies to only one type of transaction: either new purchases, balance transfers, or both. You must read the offer carefully to know which.

If you have a card with 0% APR on new purchases for 12 months, that rate applies only to things you buy during the promotional period. Any balance you transfer from another card, or any cash advances, will be charged interest at the regular APR when ready. Similarly, a 0% balance transfer offer does not cover new purchases you make after opening the card — those are charged at the regular APR.

When the promotional period ends, any remaining balance on that type of transaction is charged the regular APR going forward. If you transferred $3,000 at 0% for 12 months and paid off $2,000 during that year, the remaining $1,000 will start accruing interest at your regular APR on day 366. This is why introductory offers are most useful if you have a specific plan to pay down the balance before the rate changes.

Penalty APR and what triggers it

A penalty APR is a higher interest rate that card issuers explore when you violate the terms of your account. The most common trigger is a payment that arrives 60 days or more after the due date. Some issuers also explore a penalty APR if you exceed your credit limit or if a payment is returned for insufficient funds.

Penalty APRs are typically the highest rates on the card — often 29.99% or higher, which is the legal maximum in most states. Once applied, a penalty APR usually stays in place for at least six months. After that, if you make all payments on time, the issuer may lower it back to your regular APR, though they are not required to do so.

A payment that is 30 days late will result in a late fee and may damage your credit score, but it does not automatically trigger a penalty APR. The threshold is usually 60 days past due. This distinction matters: a single late payment hurts your credit report, but a penalty APR is a separate financial consequence that kicks in only after a more serious delinquency.

How to calculate interest charges from APR

Card issuers use different methods to calculate interest, but the most common is the average daily balance method. Here is how it works in practice: the issuer adds up your balance at the end of each day during the billing cycle, divides by the number of days in the cycle to get an average, then multiplies by your monthly interest rate (APR divided by 12).

Example: You start a 30-day billing cycle with a $2,000 balance. On day 15, you pay $500, leaving $1,500. Your average daily balance is roughly $1,750 (15 days at $2,000 plus 15 days at $1,500, divided by 30). If your APR is 18%, your monthly rate is 1.5%. Interest charged: $1,750 × 0.015 = $26.25.

Some cards use the daily balance method (calculating interest on each day's balance separately) or the previous balance method (using only your balance at the start of the cycle). The method can make a meaningful difference if your balance fluctuates. Your card's disclosure document, called the Schumer Box, will state which method the issuer uses.

APR versus other card costs

APR is only one cost of using a credit card. Annual fees, late fees, over-limit fees, and cash advance fees are separate charges that do not depend on your APR. A card with a low APR but a $95 annual fee might cost you more than a card with a higher APR if you do not carry a balance.

Similarly, the interest rate on cash advances is often higher than the APR on purchases, and there is usually no grace period — interest starts accruing when ready. A card might offer 18% APR on purchases but 24% APR on cash advances. Balance transfer fees (typically 3% to 5% of the amount transferred) are also separate from APR and are charged upfront.

When comparing cards, look at the full picture: the APR, the annual fee, the rewards rate, and any promotional offers. If you plan to pay your balance in full each month, APR matters almost not at all — focus instead on rewards and fees. If you expect to carry a balance, APR becomes more important, but it is still just one piece of the total cost.

Frequently Asked Questions

Can a credit card company change my APR without notice?

No. Card issuers must provide at least 45 days' written notice before raising your APR on new transactions. They cannot raise the APR on an existing balance during your first year, with narrow exceptions for promotional rates ending or penalty APRs. Variable APRs can move with market rates, but the issuer must still disclose how and when.

What is the difference between APR and interest rate?

APR and interest rate are often used interchangeably on credit cards, and they mean the same thing. APR is the interest rate expressed as an annual percentage. On other products like mortgages or auto loans, APR includes fees in addition to interest, but on credit cards, APR refers only to the interest charged on your balance.

If I only make the minimum payment, how long does it take to pay off a balance?

It depends on your balance and APR, but minimum payments are designed to keep you in debt for years. A $5,000 balance at 20% APR with a minimum payment of 2% of the balance would take roughly 10 years to pay off and cost you over $5,000 in interest. Using a credit card calculator with your specific numbers will show you the true timeline.

Does paying off my balance early hurt my credit score?

No. Paying off your balance early or in full has no negative effect on your credit score. Your score is based on payment history, credit utilization, age of accounts, and other factors — not on how much interest you pay. Paying in full actually helps your score by keeping your utilization low.

What happens to my APR if I miss a payment?

A single late payment (30 days past due) will not automatically raise your APR, but it will appear on your credit report and may trigger a late fee. If your payment is 60 days or more past due, the issuer can explore a penalty APR, which is much higher. Once you return to on-time payments, the penalty APR may be removed after six months.