Credit Card Validator

How to use

1. 1Pick a mode at the top: Single card to validate one number with a step-by-step Luhn breakdown, or Batch list to validate one number per line.
2. 2Type or paste the card number. Spaces, dashes, and other punctuation are ignored, so the standard 4-4-4-4 print format works fine.
3. 3Read the result. The brand pill, expected length, and Luhn outcome appear together so you know what failed if the number is invalid.
4. 4Click any brand under Generate test card number to load a sandbox number. The number passes Luhn but cannot be charged on a real network.
5. 5Use Copy digits, Copy formatted, or Copy masked to grab the result, or Copy valid only in batch mode to keep the passing entries.

About this tool

Credit Card Validator checks payment card numbers (PAN) entirely in your browser using the Luhn algorithm defined in ISO/IEC 7812. Paste or type a number and the tool strips non-digits, identifies the issuing brand from its IIN/BIN prefix (Visa, Mastercard, American Express, Discover, JCB, Diners Club, UnionPay, Maestro), checks the digit length against that brand's published rules, and runs the Luhn checksum. The result panel shows the detected brand, the expected length and CVV size, and a step-by-step Luhn breakdown with each digit, whether it was doubled, and the running sum, so the math is easy to verify and the tool doubles as a teaching aid for the algorithm. A separate batch mode accepts one number per line, validates the entire list at once, shows valid and invalid counts, marks each row, and exposes a single click to copy the valid-only list back to the clipboard, which is useful for cleaning fixture data and exported test sets. The tool also includes a generator for the publicly documented test card numbers used in sandbox environments by the major payment processors. These numbers pass Luhn and have valid brand prefixes, so they exercise checkout validation cleanly, but they cannot be charged on any real network. Brand detection prioritizes the longest matching prefix, so a four-digit Mastercard 2-series BIN beats the single-digit Visa 4 prefix correctly. Useful for QA of checkout forms, fixture generation, mocking payment data in tests, debugging form validation, learning how the Luhn algorithm works, and quickly recognizing the issuing network for an unknown number. Validation runs locally on your device, so any number you paste here never leaves your browser. Avoid pasting real customer card data into any web form, including this one; use the test number generator instead.

Free to use. Works in your browser. No signup, no login.