VISA, Master Card and Discover: 3 Digit Card Verification Number

The verification number is a 3-digit number printed on the back of your card. It appears after and to the right of your card number as such:

American Express (AMEX): 4 Digit Card Verification Number

The American Express verification number is a 4-digit number printed on the front of your card. It appears after and to the right of your card number as such: