American Express uses a four-digit security code, not three. This is one of the key differences between Amex and other major card networks like Visa and Mastercard, which use three-digit codes. If you’re checking out online and wondering which number to enter, look for the four-digit code printed on the front of your American Express card.
Where to Find It on Your Card
On a physical American Express card, the four-digit security code is printed on the front. It’s typically located above and to the right of your card number, though the exact placement can vary slightly depending on the card design. The code is printed flat on the card rather than embossed, so it won’t be raised like the card number on older card styles.
This is the opposite of most Visa and Mastercard cards, where the three-digit code sits on the back, usually near or on the signature strip. Because the security code and card number are on different sides, someone who snaps a quick photo of one side of the card won’t automatically capture both pieces of information.
Why Amex Uses Four Digits
A four-digit code is simply harder to guess than a three-digit one. A three-digit code has 1,000 possible combinations (000 through 999), while a four-digit code has 10,000. That extra digit makes brute-force guessing ten times less likely to succeed. The code itself works the same way regardless of length: it confirms that the person making the purchase has physical access to the card, not just a stolen card number from a data breach.
What Online Checkout Forms Expect
Most online stores label the security code field as “CVV,” “CVC,” or “Security Code” and accept both three-digit and four-digit entries. If you enter your American Express card number, a well-designed checkout page will recognize the card network and allow four digits in the security field.
Occasionally, you’ll run into a payment form that caps the field at three characters. This usually means the merchant’s checkout system wasn’t built to handle American Express cards. If the form won’t let you type a fourth digit, the site may not accept Amex at all. Look for the American Express logo among the accepted payment icons before trying again, or use a different card.
Virtual and Digital Wallet Cards
If you use an Amex virtual card number for online purchases, the process stays the same. American Express dynamically generates a fresh four-digit code each time you pay with your virtual card number, so you don’t need to memorize or look up the code yourself. The checkout experience mirrors a physical card transaction, just with a rotating code for added security.
When you pay in person using a digital wallet like Apple Pay or Google Pay, the terminal handles authentication differently and won’t ask for a security code at all. The code only comes into play for online and phone purchases where you’re manually entering card details.
Different Names for the Same Thing
You’ll see this code called by several names depending on the card network and the website you’re using. American Express officially calls it a Card Identification Number (CID), while Visa uses CVV2 and Mastercard uses CVC2. In practice, most checkout pages just say “CVV” or “Security Code” regardless of which network issued your card. They all serve the same purpose: proving you have the physical card in hand.