A credit card is a plastic card that lets you borrow money from a bank or card issuer to pay for things right now, then pay that money back later

When you use a credit card, you are not spending your own money. The card issuer — usually a bank — is lending you the money. You get a bill each month showing everything you charged, and you decide how much of that bill to pay. If you pay the full amount, you owe nothing extra. If you pay only part of it, the issuer charges you interest on the money you still owe, and that interest gets added to your next bill.

The card issuer makes money from the interest you pay, and sometimes from fees they charge merchants when you swipe or tap your card. You get something too: the ability to buy things without cash in your pocket, a record of your spending, and the chance to build a credit history that lenders will look at later when you want to borrow for a car or a house.

Key Takeaways

  • A credit card is a loan from a bank that you can use repeatedly — you borrow money to buy something, then pay it back on a monthly bill.
  • If you pay your full bill each month, you pay no interest; if you pay only part of it, interest charges are added to what you still owe.
  • Credit card companies report your payment history to credit bureaus, which build a credit score that affects your ability to borrow money in the future.
  • Every credit card has a credit limit — the maximum amount you can borrow at one time — set by the issuer based on your income and credit history.
  • Credit cards charge interest rates that vary widely by issuer and by your creditworthiness, and some cards charge annual fees while others do not.

How a credit card transaction actually works

When you hand a cashier your credit card or type the number into a website, several things happen in the background. The merchant's payment system sends your card number to the card issuer to check whether the charge is allowed. The issuer looks at your credit limit — the maximum you can borrow — and decides yes or no in seconds. If yes, the transaction goes through and you walk out with your purchase.

The merchant does not get paid when ready. The card issuer pays the merchant a few days later, minus a small fee. Meanwhile, that purchase shows up on your account. At the end of your billing cycle — usually a month — the issuer sends you a statement listing every charge, the total you owe, and a minimum payment amount (usually 1 to 3 percent of what you owe). You then have a choice: pay the whole thing, pay the minimum, or pay something in between.

Interest, fees, and what they cost you

The annual percentage rate, or APR, is the interest rate the card issuer charges on money you borrow. It varies by card and by your credit history. A person with excellent credit might get a card with a 15 percent APR, while someone with poor credit might face 25 percent or higher. That rate is applied monthly to whatever balance you carry.

Here is what that means in dollars: if you owe $1,000 and your APR is 20 percent, the issuer charges you roughly $17 in interest that month (20 percent divided by 12 months). If you pay only the minimum and keep charging, that interest keeps growing. Many cards also charge a late fee if you miss a payment, an annual fee just for having the card, or a foreign transaction fee if you use it outside the United States. Some cards charge none of these; others charge all of them.

Credit limits and how they are set

When you open a credit card account, the issuer assigns you a credit limit — say, $2,000 or $5,000. That is the most you can borrow at any one time. The issuer decides this limit based on your income (which you report on the process), your credit history, and how much debt you already carry. Someone with no credit history might get a $500 limit; someone with years of on-time payments might get $10,000 or more.

Your credit limit is not information programs. It is the ceiling on how much you can borrow. If you charge $1,800 on a $2,000 limit, you have $200 left to use. If you try to charge $300, the transaction will be declined. You can ask the issuer to raise your limit, and they may do so if your income has gone up or your payment history is strong. Some issuers raise limits automatically over time.

How credit cards build your credit score

Every month, your credit card issuer reports your payment history to three companies called credit bureaus: Equifax, Experian, and TransUnion. They track whether you paid on time, how much of your credit limit you used, and how long you have had the account. Over time, this information becomes your credit history, and the bureaus use it to calculate a number called your credit score.

Your credit score ranges from 300 to 850, and lenders use it to decide whether to lend you money and at what interest rate. A higher score means lenders see you as less risky. If you pay your credit card bill on time every month and keep your balance low, your score goes up. If you miss payments or max out your card, your score drops. This matters because a higher score can save you thousands of dollars in interest when you borrow for a car, a house, or anything else.

Rewards, cash back, and what they actually cost

Many credit cards offer rewards: you earn points, miles, or cash back for every dollar you spend. A card might give you 1 percent cash back on everything, or 3 percent on groceries and gas and 1 percent on everything else. At first glance, this looks like information programs — you spend $1,000 and get $10 back.

The catch is that rewards cards often charge an annual fee, and they tend to have higher interest rates than cards with no rewards. If you carry a balance and pay interest, the interest you pay will almost always be more than the rewards you earn. Rewards only make sense if you pay your full bill every month, so the interest rate does not matter. If you do, a rewards card can be genuinely useful — you get cash or points back on spending you were going to do anyway.

Debit cards versus credit cards

A debit card looks like a credit card and works at the same checkout, but it is not a credit card. When you use a debit card, money comes directly out of your bank account. You are spending your own money, not borrowing. There is no bill, no interest, and no credit score impact. You cannot spend more than you have in the account.

A credit card is the opposite: you borrow first and pay later. The tradeoff is that credit cards let you build a credit history and offer fraud protection that debit cards often do not. But they also make it straightforward to spend more than you intended, because the money does not leave your account right away. Many people use both: a debit card for everyday spending and a credit card for larger purchases or to build credit.

Frequently Asked Questions

What happens if I do not pay my credit card bill?

If you miss a payment, the issuer charges a late fee and reports the missed payment to the credit bureaus, which damages your credit score. If you stay behind for 30, 60, or 90 days, the damage gets worse. After 180 days of no payment, the issuer may close your account and sell your debt to a collection agency, which will pursue you for the money.

Can I use a credit card to withdraw cash from an ATM?

Yes, but it is expensive. A cash advance charges a higher interest rate than regular purchases — often 25 percent or more — and starts charging interest when ready, with no grace period. You also pay a fee, usually 3 to 5 percent of the amount you withdraw. Avoid cash advances unless it is truly an emergency.

What is a grace period?

A grace period is the time between when you make a purchase and when interest starts to accrue. Most credit cards give you 21 to 25 days. If you pay your full bill within that window, you owe no interest. If you carry a balance, interest starts the day after the grace period ends.

Do I need good credit to get a credit card?

No. If you have no credit history or poor credit, you can get a secured credit card, which requires you to put down a cash deposit (usually $200 to $2,500) that becomes your credit limit. You use it like a regular card, and after a year or so of on-time payments, the issuer may convert it to a regular card and return your deposit.

What is the difference between a credit card and a line of credit?

Both let you borrow money and pay it back over time, but a credit card is designed for repeated small purchases, while a line of credit is usually a larger amount you borrow once and pay back in installments. A home equity line of credit, for example, lets you borrow against the value of your house for a big expense like a renovation.