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About this tool
Check whether a card number passes the Luhn checksum and identify the issuer — Visa, Mastercard, American Express and more. See the correctly grouped, formatted number and its length. Useful for testing payment forms and understanding card formats. Everything runs locally in your browser — your card number is never uploaded.
How to use
- Type or paste a card number (spaces or dashes are ignored).
- Read the validity result and detected brand instantly.
- Copy the correctly formatted number.
Is my card number sent to a server?
No. Validation runs entirely in your browser.
What is the Luhn algorithm?
A checksum used to catch accidental errors in card numbers. Passing Luhn does not confirm a card is real or active.