 TITLE: What Is a CVV Number on a Credit Card? CONTENT: A CVV is a number on your credit card or debit card that's in addition to your credit card number and expiration date (and it's not the same as your PIN). Different issuers have slightly different names and locations for them. The CVV for Visa, Mastercard and Discover credit cards is a three-digit number on the back of your card, to the right of the signature box. American Express uses a four-digit code, which they call the card identification number (CID). The American Express CID is on the front of the card above the account number.\nWhen you present your card in person, you might be asked to show your ID or enter a PIN to verify the transaction. But it's not so easy to authenticate someone's identity for a purchase online or on the phone, so issuers started using these numbers as another barrier to fraud.\nIn transactions where the card isn't present, meaning online or on the phone, merchants often now ask for this number in addition to your credit card number and expiration date. It's not always required, but it helps ensure they're (most likely) getting payment from the legitimate cardholder.\nIf a thief is able to steal your credit card number and expiration date but doesn't have your CVV, they can't buy anything from merchants that require purchasers to provide a CVV. END