Luhn Checker — Validate Card Number Online

Paste a card or identifier number to run the Luhn checksum. Does not verify issuer or account — paste-only.

—Luhn check

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How to use

  1. Paste the numeric string (spaces and dashes are ignored).
  2. See pass or fail for the Luhn checksum instantly.
  3. Use before form validation or payment integration testing.

Frequently asked questions

What is the Luhn algorithm?

A checksum formula used by credit cards and many ID numbers to catch single-digit typos.

Does passing Luhn mean the card is real?

No. It only validates the checksum — not issuer, expiry, or account status.

Are spaces and dashes supported?

Yes. Non-digit characters are stripped before validation.

Is my number sent to a server?

No. The Luhn check runs entirely in your browser.

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