Credit Card Validator
/credit-card-validatorValidate credit card numbers with the Luhn algorithm. Detect the card network and check formatting.
Typing a card number one digit off causes failed payments and embarrassment. This validator checks numbers against the Luhn algorithm and identifies the issuing network — Visa, Mastercard, Amex, and more. It also flags formatting issues like wrong lengths. Validation happens locally, with the number never transmitted.
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FAQ
Frequently asked questions
Everything you need to know about credit card validator.
How does the validation work?
The number is checked with the Luhn algorithm, which verifies the checksum digit and catches most accidental typos and transpositions.
Which networks are detected?
Visa, Mastercard, Amex, Discover, JCB, and UnionPay are detected by their number prefixes and typical lengths.
What does a valid result mean?
A valid result confirms the number passes the Luhn checksum and matches a known card network pattern, which does not guarantee the card is real or funded.
Is my card number safe?
Yes. Validation runs entirely in your browser, and nothing is stored or transmitted anywhere during the check.
Why does formatting matter?
The tool accepts numbers with spaces or dashes, strips them, and then validates, so formatting does not affect whether a number passes the checksum.
What is the Amex pattern?
American Express cards start with 34 or 37 and use 15 digits, while Visa starts with 4 and Mastercard with 51 through 55 or newer 2-series ranges.
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