Card Number Checksum Validator
Check digit length and the Luhn checksum of a card-number test fixture.
Processing stays in your browser. A matching checksum does not establish that a card exists, is active, or is authorized. Use test numbers rather than real payment details.
How to use the card number checksum validator
Check digit length and the Luhn checksum of a card-number test fixture. Complete the test card number fields above. Choose Run tool, review the output, then copy or download the result.
Example
4242 4242 4242 4242 passes Luhn; changing its last digit fails.
Good to know
A matching checksum does not establish that a card exists, is active, or is authorized. Use test numbers rather than real payment details.