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Credit Card Validator (Luhn)

Check if a card number is well-formed and pass the Luhn check — without sending it anywhere.

Test with any fake number — 4111 1111 1111 1111 always passes. Never enter a real card anywhere online.

What the Luhn check does

It confirms the number is structurally valid (the right number of digits for its brand, with a valid check digit). It does not check whether the card is real, active, or has funds. Use Stripe’s test cards in development, never real ones.

About this tool

Paste a card number and the tool runs the Luhn algorithm locally, identifies the card brand (Visa, MC, Amex, etc.), and flags obvious length issues. Educational — never enter real card numbers anywhere online.

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