Credit Card Validator
Check whether a card number passes the Luhn algorithm and see its brand.
How to use
- 1Paste the card number.
- 2Click Process.
- 3See if it is valid using the Luhn algorithm.
About
Validates the card number using the Luhn algorithm, useful for catching typos. Does not charge anything.
How to validate a card number correctly
The card validator applies the Luhn algorithm to check whether a card number is structurally valid and, when possible, identifies the brand by its prefix. It helps catch typos in payment forms.
The Luhn algorithm sums the card digits with alternating weights to produce a check digit. If the final number does not match the calculation, the card has a wrong or swapped digit.
The BIN (the first 6 digits) identifies the brand: Visa starts with 4, Mastercard with 51 to 55 (or 2 in the new range), and American Express with 34 or 37. The tool uses these prefixes to suggest the brand.
It is crucial to understand that validating a number does not confirm the card has funds, is active, or belongs to someone. A number can pass Luhn and be completely fictitious, with no real issuer.
Examples
- 4111 1111 1111 1111 → valid under Luhn (Visa pattern).
- 4111 1111 1111 1112 → invalid (fails the check digit).
Limitations
- Validation is structural: it does not check balance, expiry, issuer, or whether the card is blocked.
- Numbers generated for testing pass the algorithm but cannot be used in real transactions.
How to use the card validator
- 1Type or paste the card number (with or without spaces).
- 2Click Process.
- 3See whether it is valid and the suggested brand.
Frequently asked questions
Does the validator query the bank or the brand?
No. Validation is local and mathematical (Luhn), with no connection to issuers or card networks.
Can I test with a sample card?
Yes, test numbers like 4111 1111 1111 1111 (Visa) are accepted to validate the algorithm, but they do not work in real purchases.
What is the Luhn algorithm?
It is a simple checksum that detects most typing errors and digit transpositions in card numbers.