Card BIN / Format Reference & Luhn Checker

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Look up the IIN/BIN prefix ranges, number lengths and CVV lengths of every major card network, and instantly Luhn-check and pretty-format any card number — client-side, nothing stored.

Type a card number to check it
Detected network –
Length check –
Try a sample:
This only checks the number's mathematical validity (Luhn checksum + format) — it does NOT tell you whether a card is real, active or has funds. Nothing you type is stored or sent anywhere; it all runs in your browser. Never enter a real card number on any site you don't trust.

Card network reference

IIN/BIN prefix ranges, number lengths and CVV lengths for the major card networks.

Network IIN / BIN prefixes Length CVV Luhn-valid Copy
No networks match your search
Try a different network name or prefix.
Prefix (IIN/BIN) ranges and lengths follow each network's published numbering rules and can change over time; some issuers use sub-ranges not listed here. The Luhn check and length check verify only the number's structure — not that a card exists or is usable.

About Card BIN / Format Reference & Luhn Checker

This reference covers the numbering formats of the major payment card networks — Visa, Mastercard, American Express, Discover, Diners Club, JCB, UnionPay, Maestro, RuPay, Mir and more. For each network it lists the IIN/BIN prefix ranges, the valid number lengths, the CVV length and whether the network uses the Luhn checksum.

A built-in checker validates any number as you type: it detects the network from the prefix, formats the digits with that network’s real spacing (4-6-5 for American Express, 4-4-4-4 for most others), counts the digits against the expected lengths and runs the Luhn mod-10 checksum. Sample numbers for Visa, Mastercard, Amex and Discover are one click away.

Everything happens locally in your browser — the number is never transmitted or stored — which makes the page a safe aid for developers testing checkout forms, support teams recognizing card types from a prefix, and anyone curious why card numbers are structured the way they are.

How to use Card BIN / Format Reference & Luhn Checker

  1. Type or paste a card number into the checker — it is formatted live with the detected network’s digit grouping.
  2. Read the verdict strip for the Luhn checksum result, plus the detected network and the length check with expected digit counts.
  3. Try one of the sample buttons (Visa, Mastercard, Amex, Discover) to see a passing number instantly.
  4. Search the reference table to find a network’s BIN prefixes, valid lengths and CVV length, and copy any row.

Frequently asked questions

The Luhn algorithm is a mod-10 checksum that nearly every card network builds into its numbers. It catches typos like a single wrong digit or a swapped pair. Passing Luhn means the number is well-formed — not that a real card exists.

By its IIN/BIN prefix — the first few digits. Numbers starting with 4 are Visa, 51–55 and 2221–2720 are Mastercard, 34 and 37 are American Express, and so on, following each network’s published ranges in the table.

The check runs entirely in your browser; the number is never sent to a server, stored or logged, and the page says so explicitly. Even so, the intended use is test and sample numbers, not sharing real card details.

Amex numbers are 15 digits grouped 4-6-5, unlike the 16-digit 4-4-4-4 pattern most networks use. The checker applies each network’s genuine spacing automatically once the prefix is recognized, and Amex cards also use a 4-digit CVV.

Almost all do, but there are exceptions — the table flags networks like UnionPay where some ranges do not Luhn-validate. That is why the checker reports the detected network alongside the checksum verdict instead of relying on Luhn alone.

Yes, the reference table, the Luhn checker and the sample numbers are all free to use without an account.
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