Is a credit card security code 3 or 4 digits? Security codes are typically three digits, but it could vary by card network. For example, American Express credit card security codes are four digits.

Key takeaways. Credit card security codes are three-digit codes on the back of your card (four-digits on the front if you have an American Express card) used to verify that have the physical card.

These three- or four-digit numbers provide an additional layer of security. Here is what you need to know about credit card security codes and how to find them by issuer.