Credit Card Number Validation Regex Pattern

How it works

This pattern checks the card number prefix and length for the four major card networks: Visa (starts with 4, 13 or 16 digits), Mastercard (starts with 51–55, 16 digits), Amex (starts with 34 or 37, 15 digits), and Discover (starts with 6011 or 65, 16 digits). Always combine with a Luhn algorithm check for real validation.

Test Cases

Should Match

4111111111111111
5500005555555559
378282246310005

Should NOT Match

1234567890123456
411111111111
4111 1111 1111 1111

Quick Summary

Validates credit card numbers for Visa, Mastercard, Amex, and Discover by checking prefix and length. Strip spaces and dashes before applying. Always combine with a Luhn algorithm check, regex alone cannot detect invalid card numbers.

Key Takeaways

Checks card network prefix and digit count, not cryptographic validity
Must be combined with Luhn algorithm check for real card number validation
Strip all spaces and dashes before applying this pattern
Never log or store raw card numbers, use a PCI-compliant tokenization service

Use Cases

When to use it

Client-side format validation before submitting to a payment processor
Detecting card type to show the correct card logo in a payment form
Sanitizing test data in development environments

Watch out

Common Mistakes

Using regex as the only validation, always run the Luhn check too
Storing or logging card numbers, this is a PCI DSS violation
Not stripping spaces/dashes from user input before matching

FAQ

Credit Card Number Validation, Frequently Asked

What is the Luhn algorithm?

The Luhn algorithm is a checksum formula used to validate credit card numbers. It detects single-digit errors and most transposition errors. Implement it alongside this regex.

Should I validate card numbers myself?

For production payments, use a PCI-compliant processor like Stripe or Braintree. They handle validation, tokenization, and compliance for you.