Credit Card Validator
Validate credit card numbers using the Luhn algorithm and identify the card issuer by its prefix. This is an educational tool for learning how card validation works - please use only test numbers, never real card data.
FAQ
The Luhn algorithm (mod 10) is a simple checksum formula used to validate identification numbers, including credit card numbers. It catches single-digit errors and most adjacent transpositions. It's a basic integrity check - not a security measure.
Each card network uses a specific range of prefixes (IIN/BIN): Visa cards start with 4, Mastercard with 51�55 or 2221�2720, Amex with 34 or 37, Discover with 6011 or 65. The tool matches these prefixes to identify the issuer.
No. Luhn only validates the number format — not whether the card has funds, hasn't expired, or was issued by a real bank. It's a first-line check to catch typos before submitting to payment processors. Real validation involves checking with the card network (Visa, Mastercard, etc.).
By checking the first digits (IIN/BIN): Visa starts with 4, Mastercard 51-55 or 2221-2720, Amex 34 or 37, Discover 6011 or 65. Card number length also helps: Visa is 13 or 16 digits, Amex is 15, most others are 16.
No. This is an educational tool. While all logic runs client-side in your browser, it's never safe to enter real financial data on any website. Use well-known test numbers like 4111111111111111 (Visa) or 5500000000000004 (Mastercard).
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