Credit card check digit

Client

The credit card check digit is the final digit making the Luhn sum divisible by ten. When forms reject a card, the check digit is a frequent single-character error—paste the full PAN to see pass/fail.

Check digit vs CVC

Luhn check digit is part of the PAN digit string. Card verification value (CVC) is printed separately and validated by the issuer on authorization—not by this tool.

Sensitive data: checks run only in your browser. Prefer processor-published test card numbers, never live PANs on shared devices.
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Spaces and dashes are stripped before counting digits and running Luhn. Card-network labels come from common public BIN/IIN ranges—they may mismatch exotic co-branded or new ranges.

16 digits after cleanup

Likely network: Visa

Luhn checksum: passes — algorithm-only; does not mean the card is active or genuine.

Common use cases

  • Debug checkout typos without calling authorization APIs.
  • Explain check digit role in payments literacy training.

Common mistakes to avoid

  • Confusing check digit with CVC/CVV

    CVC is a separate security code—not the Luhn check digit.

FAQ

Which digit is the Luhn check digit?

The rightmost digit of the primary account number in standard Luhn validation.

Common search terms

Phrases people search for that match this tool. See the full long-tail keyword index.

  • credit card luhn check online
  • visa mastercard bin checker browser
  • payment card checksum validator no upload
  • validate primary account number luhn locally
  • discover amex prefix checker heuristic online

More tools

Related utilities you can open in another tab—mostly client-side.