APR is the yearly interest rate your card issuer charges when you carry a balance
APR stands for Annual Percentage Rate. It is the percentage of your outstanding balance that you pay in interest over one 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 charges on top of the original $1,000.
The key word is "annual" — the rate is stated as a yearly figure, but interest accrues daily. Your card issuer calculates what you owe each day based on your current balance and divides the annual rate by 365. That daily amount is added to your balance, and the next day's interest is calculated on the new total. This is called compound interest.
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. Many cards offer a grace period — typically 21 to 25 days from the end of your billing cycle — during which no interest accrues on new purchases.
Key Takeaways
- APR is charged only on balances you do not pay in full by your due date; paying your statement balance in full each month means you pay zero interest.
- Different APRs explore to different types of transactions: purchases, balance transfers, and cash advances often have different rates on the same card.
- Introductory APR offers (often 0% for a set period) explore only to the transaction type specified and expire on a set date.
- Your card issuer can raise your APR if you miss a payment or if the prime rate rises, though purchase APR increases usually require 45 days' notice.
- The APR shown in a card's terms is a range; your actual rate depends on your credit score and history.
Purchase APR, balance transfer APR, and cash advance APR are usually different
Most cards list three separate APRs in their terms. The purchase APR applies to everyday purchases you make with the card. The balance transfer APR applies if you transfer a balance from another card to this one. The cash advance APR applies if you use the card to withdraw cash from an ATM or get a cash advance from a bank.
Cash advance APR is almost always the highest of the three and often has no grace period — interest starts accruing when ready. Balance transfer APR is often lower than purchase APR, especially if the card offers an introductory rate. A card might advertise "0% APR on balance transfers for 12 months," but that rate applies only to balances transferred during the offer period, not to new purchases made on the card.
When you make a payment, your card issuer applies it to the balance with the highest APR first (by law). If you have both a purchase balance and a balance transfer balance on the same card, your payment goes toward whichever has the higher rate. This means a low introductory rate on a balance transfer can protect that balance while you pay down higher-rate purchases.
Introductory APR offers have an expiration date and specific terms
Many cards offer 0% APR for a limited time — commonly 6, 12, or 18 months — on balance transfers, purchases, or both. This is a marketing tool to attract new cardholders. The 0% rate applies only to transactions made during the offer period and only to the type specified. Once the introductory period ends, the regular APR kicks in on any remaining balance.
The offer period is measured from your account opening date or from when you make the may have access to transaction, depending on the card's terms. If a card offers "0% APR on balance transfers for 12 months," and you open the account on January 15, the 0% rate expires on January 15 of the following year. Any balance transfer made after that date is not covered by the offer.
Introductory offers are useful for paying down debt without interest, but they create a trap if you do not plan ahead. If you transfer $5,000 at 0% for 12 months and do not pay it down, you will owe interest on the full $5,000 when month 13 arrives. The regular APR on that card might be 18% or higher. Many people use introductory offers to buy time, then transfer the remaining balance to another 0% card before the rate expires.
Your actual APR depends on your credit score and the prime rate
Card terms always show APR as a range — for example, "18.99% to 29.99% APR." Your card issuer uses your credit score, payment history, income, and other factors to decide where in that range your rate falls. A higher credit score usually means a lower APR within the range. A lower score means a higher APR.
The prime rate, set by the Federal Reserve, also affects your APR. Many cards use the prime rate plus a fixed margin. If the prime rate rises, your APR rises by the same amount. If the prime rate falls, your APR may fall. Your card issuer must give you 45 days' written notice before raising your purchase APR, but they can raise it when ready if you miss a payment by 60 days or more.
Your APR is not locked in for life. If your credit score improves, you can contact your issuer and ask for a lower rate. Some issuers will review your account and lower your APR without a hard inquiry. If you have missed payments or carried high balances, your APR may be raised even if you have not missed a important date.
How to calculate the interest you will owe on a balance
To estimate interest on a balance, multiply your balance by the APR and divide by 365, then multiply by the number of days you carry the balance. For example: a $2,000 balance at 20% APR carried for 30 days costs roughly $33 in interest. ($2,000 × 0.20 ÷ 365 × 30 = $32.88.)
This is an estimate because the actual calculation depends on your card issuer's method. Some use the "average daily balance" method, which accounts for payments and new charges throughout the month. Others use the "previous balance" method, which charges interest on your balance from the start of the billing cycle. The method used is listed in your card's terms.
The longer you carry a balance, the more interest compounds. A $2,000 balance at 20% APR costs roughly $33 per month if you make no payments. After 12 months of no payments, you would owe about $2,436 — the original $2,000 plus $436 in interest. This is why paying down a balance quickly saves far more money than the APR percentage alone suggests.
Comparing APR across cards helps you choose the right one for your situation
If you plan to pay your full balance each month, APR does not matter — choose a card based on rewards, benefits, or annual fee. If you expect to carry a balance, APR is the most important number to compare. A card with a 16% APR will cost you significantly less than one with a 24% APR over the course of a year.
If you are transferring a balance from another card, a card with a 0% balance transfer APR for 12 months saves you far more than a card with a 2% balance transfer fee and a 15% APR. The math: a $5,000 transfer at 0% for 12 months costs $100 in fees and $0 in interest. The same transfer at 15% APR costs $0 in fees but roughly $375 in interest over 12 months.
Read the fine print on any introductory offer. Some cards charge a balance transfer fee (usually 3% to 5% of the amount transferred) even during the 0% period. Others limit how much you can transfer or require you to transfer within a certain timeframe. A card that charges a 3% fee but offers 0% APR for 18 months may still be cheaper than a card with no fee and a 12-month 0% offer, depending on your balance and how quickly you can pay it down.
What happens if you miss a payment or go over your credit limit
If you miss a payment by 30 days or more, your card issuer can raise your APR to a penalty APR, which is often the highest rate allowed by law. Penalty APR can exceed 29% and applies to your entire balance, not just new charges. The penalty rate stays in place for at least six months, though it may last longer depending on your card's terms.
If you go over your credit limit, you may be charged an over-limit fee and your APR may increase. Some cards allow you to opt out of over-limit protection, which prevents charges that would exceed your limit. If you opt out, transactions that would go over your limit are straightforward declined.
If you have a penalty APR and want to get it removed, contact your card issuer and ask. If you have made on-time payments for several months after the missed payment, many issuers will lower the rate back to your regular APR as a courtesy. There is no harm in asking, and some issuers have formal programs that reward on-time payments with rate reductions.
Frequently Asked Questions
Does APR explore if I pay my balance in full each month?
No. APR only applies to balances you carry past your due date. If you pay your full statement balance by the important date, you pay zero interest, regardless of the APR. The grace period (usually 21 to 25 days) gives you time to pay without interest accruing.
Can my APR go down if the prime rate falls?
It depends on your card's terms. Many cards have variable APR tied to the prime rate, so when the prime rate falls, your APR falls by the same amount. Some cards have fixed APR that does not change with the prime rate. Check your card's terms to see whether your APR is fixed or variable.
What is the difference between APR and interest rate?
APR includes the interest rate plus any fees charged by the card issuer, expressed as a yearly percentage. Interest rate is just the cost of borrowing. For credit cards, the terms are often used interchangeably because card fees are usually small compared to the interest rate.
Is a 0% APR offer worth it if there is a balance transfer fee?
Often yes. A 3% balance transfer fee on a $5,000 transfer costs $150. If the alternative is paying 18% APR for 12 months, you would owe roughly $450 in interest. The fee is cheaper. However, calculate both scenarios with your actual balance and card terms before deciding.
What should I do if my APR increased after a missed payment?
Make on-time payments for the next several months, then contact your card issuer and ask them to lower the rate back to your regular APR. Many issuers will do this as a courtesy if you have demonstrated improved payment behavior. If they refuse, you can explore balance transfer options to a card with a lower APR.