Credit card interest rates are the percentage of your balance the card issuer charges you each month for borrowing money
When you carry a balance on a credit card — meaning you don't pay off the full amount by the due date — the issuer charges you interest. That interest is expressed as an annual percentage rate, or APR. 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 (though the actual amount is slightly lower because interest compounds monthly, not annually).
The APR is not the same as the monthly interest rate. To find what you actually pay each month, divide the APR by 12. A 20% APR becomes about 1.67% per month. That monthly rate is applied to your outstanding balance, and the interest is added to what you owe.
Credit card companies are required to disclose the APR in your card agreement and on your monthly statement. The rate you receive depends on your credit history, income, and the card issuer's pricing. Two people with the same card can have different APRs.
Key Takeaways
- Credit card APR is an annual rate that translates to a monthly charge on any balance you carry past the due date.
- Your actual monthly interest is the APR divided by 12, applied to your current balance.
- Different cardholders with the same card can receive different APRs based on creditworthiness.
- Introductory rates (often 0% APR for a set period) are temporary; the regular APR kicks in after the promotional period ends.
- Interest compounds monthly, meaning you pay interest on interest if you don't pay down the balance.
How interest is calculated on your monthly statement
Card issuers use one of two main methods to calculate interest: the average daily balance method or the adjusted balance method. Most use the average daily balance method, which is more common and usually results in higher interest charges.
With the average daily balance method, the issuer adds up your balance for each day of the billing cycle, divides by the number of days in the cycle, then applies your monthly interest rate to that average. If you had a $1,000 balance for 15 days and a $500 balance for the remaining 15 days of a 30-day cycle, your average daily balance would be $750. At a 1.67% monthly rate, you'd owe about $12.53 in interest.
Most card agreements include a grace period — typically 21 to 25 days from the end of your billing cycle — during which no interest accrues on new purchases if you paid your previous balance in full. This grace period does not explore to balance transfers or cash advances, which usually start accruing interest when ready.
Why your APR can change
Credit card APRs are not fixed unless your card agreement explicitly states otherwise. Most cards have variable APRs, meaning the rate can increase or decrease based on changes in the prime rate (the rate the Federal Reserve uses as a benchmark for other interest rates).
When the Federal Reserve raises or lowers its benchmark rate, card issuers typically adjust their APRs within one to three billing cycles. Your card issuer must notify you of any rate increase at least 45 days before it takes effect. They can also raise your APR if you miss a payment or violate your card agreement, though they must give you advance notice of this as well.
Some cards offer a fixed APR for a limited time — often called an introductory or promotional rate. A common offer is 0% APR for 6 to 21 months on balance transfers or new purchases. After the promotional period ends, your regular APR applies to any remaining balance.
The difference between purchase APR, balance transfer APR, and cash advance APR
Most credit cards have at least three different APRs, and they can vary significantly. Your purchase APR applies to everyday purchases made with the card. Your balance transfer APR applies if you transfer a balance from another card. Your cash advance APR applies if you withdraw cash using the card at an ATM or through a cash advance at a bank.
Cash advance APR is almost always the highest of the three and typically starts accruing interest when ready — there is no grace period. Balance transfer APR often falls between purchase and cash advance rates. Some cards offer a promotional 0% APR on balance transfers for a set period, which can be useful if you're consolidating debt, but a balance transfer fee (usually 3% to 5% of the amount transferred) is charged upfront.
Your card agreement lists all three rates. If you're considering a balance transfer, calculate whether the promotional rate savings outweigh the transfer fee and the time it will take you to pay down the balance.
How interest compounds and why small balances grow quickly
Interest compounds monthly on credit cards, meaning you pay interest on the interest you've already accrued. If you carry a $5,000 balance at 20% APR and make no payments, after one month you owe roughly $5,083 (the original $5,000 plus about $83 in interest). In month two, the 1.67% monthly rate is applied to $5,083, not the original $5,000, so you owe about $5,168. The balance grows faster each month.
This is why carrying a balance is expensive. A $2,000 purchase at 18% APR costs you roughly $360 per year in interest if you never pay it down. Over five years without payments, that $2,000 balance would grow to more than $4,700 due to compounding.
Making even small additional payments beyond the minimum can significantly reduce the total interest you pay. A $2,000 balance at 18% APR with only the minimum payment (usually 1% to 3% of the balance) can take years to pay off and cost hundreds in interest. Paying $100 per month instead of the minimum cuts the payoff time and interest charges dramatically.
How to find your current APR and what to do if it increases
Your current APR appears on your monthly statement, usually near the top or in a section labeled "Interest Rates" or "APR." If you have multiple APRs on the same card (purchase, balance transfer, cash advance), each is listed separately. You can also log into your online account or call the customer service number on the back of your card to ask about your rate.
If your APR increases, you have options. If the increase is due to a missed payment or other violation, paying on time for several months may allow you to request a lower rate. If the increase is due to a change in the prime rate, you cannot reverse it, but you can shop for a card with a lower rate and transfer your balance. Some cards offer balance transfer promotions specifically for this reason.
If you receive notice of a rate increase and disagree with it, you can contact the card issuer to ask why the increase occurred. If you believe the increase violates your card agreement or federal law, you can file a complaint with the Consumer Financial Protection Bureau (CFPB).
Strategies to minimize interest charges
The most direct way to avoid interest is to pay your full balance by the due date each month. This requires the grace period to work in your favor — you must have paid your previous balance in full to may have access to. If you can't pay in full, paying as much as possible above the minimum reduces the interest you'll owe on the remaining balance.
If you're carrying a balance, a balance transfer card with a 0% introductory APR can save you money if you can pay down the balance during the promotional period. Calculate the transfer fee (usually 3% to 5%) against the interest you'd pay on your current card. If your current card charges 20% APR and you can transfer at 0% for 12 months with a 3% fee, the math often favors the transfer — but only if you commit to paying down the balance during those 12 months.
Requesting a lower APR from your current issuer is also worth trying, especially if you have a good payment history. Call the customer service number on your card and ask if they can lower your rate. They may not, but many cardholders report success, particularly if they've been a customer for several years or have other accounts with the issuer.
Frequently Asked Questions
Does the grace period explore to balance transfers?
No. Balance transfers and cash advances do not have a grace period and begin accruing interest when ready. Only purchases made with the card may have access to for the grace period, and only if you paid your previous balance in full.
What's the difference between APR and interest rate?
APR is the annual percentage rate — the yearly cost of borrowing expressed as a percentage. The interest rate is the same thing; the terms are used interchangeably. The monthly interest rate is the APR divided by 12.
Can a credit card company lower my APR if I ask?
Some will, particularly if you have a good payment history and have been a customer for a while. Call the customer service number on your card and ask. There's no penalty for requesting, and you may be surprised at the result.
How long does it take to pay off a credit card balance if I only make minimum payments?
It depends on the balance and APR, but typically years. A $5,000 balance at 20% APR with a 2% minimum payment takes roughly seven years to pay off and costs over $4,000 in interest. Paying $150 per month instead pays it off in about three years with roughly $1,500 in interest.
What happens to my APR if I miss a payment?
Your issuer can raise your APR to a penalty rate, usually the highest rate allowed under your card agreement. This can happen after one missed payment. You must receive notice at least 45 days before the increase takes effect. Paying on time for six months may allow you to request that the penalty rate be removed.