Free Online Credit Card Validator

1. Paste the card number into the input. Spaces and dashes are stripped automatically.
2. Read the Luhn result, detected card brand and length check below.
3. If validation fails, double-check each digit — fat-fingering is the usual cause.
4. Use only published test numbers when developing — never your real card.

The Luhn algorithm is a simple checksum, invented in 1954, that catches almost every single-digit typo and most adjacent transpositions in account numbers. Every major payment card on the planet — Visa, Mastercard, American Express, Discover, JCB and Diners Club — uses Luhn for its check digit, so a number that fails Luhn cannot be a real card.

E-commerce developers use it for client-side validation before submitting to a payment processor (which charges per attempt). QA engineers generate Luhn-valid test numbers (or use the published test numbers) to exercise checkout flows. Security researchers spot-check card-data dumps for plausibility. The tool runs the Luhn checksum locally, detects the brand from the leading digits and reports the expected length per brand.

Nothing is transmitted or stored — the number lives in your browser's memory until you close the tab. As always, prefer published test card numbers when integrating against a payment gateway, and never paste a real card number into a tool you don't fully trust.