Missing payments on your credit cards can be costly and have serious consequences on your credit history. Some of those consequences include:
Late fees. Many banks assess a fee when a cardholder fails to make the minimum payment by the due date. That fee does nothing to reduce your balance – it's just extra money you'll owe on top of whatever charges you put on your card.
Interest charges. Every dollar you leave on your balance past the due date is subject to an interest charge. Credit card interest compounds quickly, so you could find that your relatively small balance balloons to a mountain of debt if you aren't paying it off regularly (ideally, in full every billing cycle). Even if you can't pay in full, at least make a payment on time to cut down on the balance that will be subject to interest.
Penalty APRs. Sometimes missing a payment triggers a penalty APR that means you'll pay a higher interest rate on your balances going forward.
Forfeited rewards. Most credit card rewards programs state in the fine print that you could forfeit rewards if your account doesn't remain in good standing.
Lost introductory/special rates. Sometimes credit cards will offer a short-term 0% interest period, but most of the fine print states that you'll lose that rate if you miss payments.
Credit damage. Miss enough payments and your credit score will take a hit. One of the big upsides of having a card in college is the opportunity to build credit before graduation, but you can also damage your credit before graduation if you don't handle your card responsibly.
Referral to collections. If you keep running up a bill and failing to make payments, the bank could refer you to a collections agency.
One other thing to keep in mind: If your credit card is co-signed by, say, your parents, your failure to pay a bill on time could also impact their credit score.
Learn more about what happens if you don't pay your credit card bill.