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Browse Fiverr →Credit Card Validator (Luhn check + brand detection)
Type a card number to verify it passes the Luhn check and detect the brand (Visa, Mastercard, Amex, Discover, JCB, Diners, UnionPay) by IIN/BIN range.
⚠ Never enter a real card number on a site you don't trust. This tool runs entirely in your browser — but the same is impossible to verify on any unknown site.
Type a card number to validate.
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How it works
What this validator checks (and doesn't)
Three checks: (1) the prefix matches a known issuer's IIN/BIN range, (2) the length is one of the valid lengths for that brand, (3) the Luhn checksum passes. If all three are true, the number is syntactically valid as a card number.
What this does NOT check: whether the card actually exists, whether it has funds, whether the cardholder authorized you to use it. That requires going through a real payment processor with proper authorization. This tool catches typos cheaply — like 1234 vs 1243 in a paste — but cannot verify the card belongs to a real account.
How the Luhn algorithm works
Luhn (1954, by IBM scientist Hans Peter Luhn) is a simple checksum: starting from the rightmost digit, double every second digit. If a doubled digit is over 9, sum its two digits (or equivalently subtract 9). Sum all the resulting digits. The total must be divisible by 10.
Luhn catches single-digit errors and most adjacent transpositions — the two most common typos when humans copy long numbers. It's not cryptographic; you can't use it to detect malicious tampering. Real card processors use Luhn as a first-line filter before more expensive backend checks.
Brand detection by IIN/BIN
The first 6-8 digits of a card number identify the issuer (Issuer Identification Number / Bank Identification Number). Major brands have well-known prefix ranges: Visa starts with 4, Mastercard with 51-55 or 2221-2720, Amex with 34 or 37, etc. We detect the brand by matching these ranges.
Brand and country can usually be inferred from the IIN. Full IIN database lookups give country, bank, card type (debit/credit), and program — used by merchants for risk scoring. We don't include a full IIN database; only the most common brand patterns.
Frequently asked questions
›Should I trust this with my real card number?
Even though we run only in your browser, you should never paste a real card number into a tool you don't trust deeply. Use one of the standard test card numbers (e.g., 4111 1111 1111 1111) for syntax checks.
›Why do I get 'invalid' for a real-looking number?
Most often the Luhn checksum fails — likely a typo. Check the digits one more time.
›Does Luhn validation prove the card exists?
No. Luhn only catches transcription errors. Many never-issued numbers pass Luhn; many real cards fail Luhn if mistyped.
›What's a 'BIN'?
Bank Identification Number — first 6-8 digits identifying the issuer. Same as IIN (Issuer Identification Number); the terms are interchangeable.
›Can I use this to generate test card numbers?
Not directly, but the standard Stripe/Visa/Mastercard test numbers are well-documented (e.g., 4242 4242 4242 4242). They pass Luhn but never charge.
›Why isn't [some brand] detected?
We support the major brands. Regional or co-branded cards may not match. Check the issuer's documentation for the IIN ranges they use.
›Does the data leave my browser?
No. Validation runs entirely in your browser with no network calls.
›Is Luhn used for things other than credit cards?
Yes — IMEI numbers, Canadian SIN, ISIN, NPI, and many other ID systems use Luhn. The algorithm is the same; only the prefix mappings differ.
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This tool provides general information and estimates only — it is not financial, investment, tax, or legal advice. Verify important figures with a qualified professional before making decisions.