The Law on Over-the-Limit Fees
Federal law prohibits credit card issuers from charging you an over-the-limit fee unless you've opted-in to have over-the-limit transactions processed. Otherwise, any transaction that would exceed your credit limit will be declined allowing you to avoid the over-limit fee.
If you have opted-in to have over-the-limit transactions processed and you exceed your credit limit, you can only be charged an over-the-limit fee for two consecutive billing cycles if your balance remains over the limit. However, if you pay your balance down and it goes over the limit again or if you get a credit limit increase and exceed the new credit limit, your credit card issuer can charge another over-the-limit fee.
How Much is the Over-the-Limit Fee
Over-the-limit fee vary by credit card issuer but are usually $39. Check your credit card agreement or the back of your credit card billing statement to find out the over-the-limit fee for your credit card.