Why are Amex cards 15 digits, not 16?

American Express uses a 15-digit number format that predates the current 16-digit standards. The format is 4-6-5 (XXXX XXXXXX XXXXX) rather than Visa/Mastercard's 4-4-4-4. Amex has not changed this to maintain compatibility with existing infrastructure.

What is the CID and how does it differ from CVV?

The CID (Card Identification Number, also called CID2 or 4DBC) is Amex's version of the card security code. Unlike Visa/MC's 3-digit CVV on the back of the card, Amex's CID is 4 digits and printed on the front of the card above the card number.

What is 3782 822463 10005?

3782 822463 10005 is Stripe's primary Amex test card that always returns a successful authorization. It's the standard Amex test number you'll see referenced across payment integration docs.

Amex Test Card Numbers — Generator

Generate Luhn-valid 15-digit American Express test card numbers with the correct 34/37 BIN prefix and 4-digit CID.

Last updated: April 2026

Card Network

Quantity (1–100)

Expiry dateCVVCardholder nameSpaced format

These are test numbers only. They will not process any real transaction. Use only in sandbox / test mode with test API credentials.

What it does

15-digit Amex format

American Express cards are 15 digits — different from Visa/Mastercard's 16. The generator produces correct 15-digit numbers.

BIN prefixes 34 and 37

All Amex cards start with 34 or 37. The generator uses both BIN prefixes.

4-digit CID

Amex uses a 4-digit Card Identification Number (CID/CID2) on the front of the card — not a 3-digit CVV.

Display format 4-6-5

Amex numbers display as XXXX XXXXXX XXXXX (4-6-5 groups), unlike Visa/MC's 4-4-4-4.

How to use Amex Test Card Numbers — Generator

1
Select Amex
Click the Amex button in the network selector.
2
Note the 4-digit CID
Amex uses a 4-digit CID. When testing Amex forms, the CID field expects 4 digits, not 3.
3
Generate
Click Generate Cards to produce Luhn-valid 15-digit Amex numbers.
4
Test 4-digit CID handling
Use these to verify your payment form accepts a 4-digit security code when the card is detected as Amex.

Testing Amex-specific form handling

Amex's unique format creates specific testing requirements. Payment forms must correctly detect Amex (prefix 34 or 37), switch to a 15-digit field length (4-6-5 display format), and show a 4-digit CID field instead of the standard 3-digit CVV. Testing with generated Amex numbers verifies all three of these behaviors — a common source of bugs in payment form implementations that only tested with Visa numbers during development.

Frequently Asked Questions

Why are Amex cards 15 digits, not 16?: American Express uses a 15-digit number format that predates the current 16-digit standards. The format is 4-6-5 (XXXX XXXXXX XXXXX) rather than Visa/Mastercard's 4-4-4-4. Amex has not changed this to maintain compatibility with existing infrastructure.
What is the CID and how does it differ from CVV?: The CID (Card Identification Number, also called CID2 or 4DBC) is Amex's version of the card security code. Unlike Visa/MC's 3-digit CVV on the back of the card, Amex's CID is 4 digits and printed on the front of the card above the card number.
What is 3782 822463 10005?: 3782 822463 10005 is Stripe's primary Amex test card that always returns a successful authorization. It's the standard Amex test number you'll see referenced across payment integration docs.