Card BIN Format Checker

About this calculator

The first six to eight digits of a payment card number are its BIN (Bank Identification Number, also called IIN), which identifies the issuing network and, often, the specific bank or program that issued the card. The leading digits follow well-known ranges: Visa cards start with 4; Mastercard uses 51–55 and the newer 2221–2720 range; American Express starts with 34 or 37; Discover starts with 6011 or 65 (among other ranges).

Alongside the BIN prefix, each network also fixes an expected total card number length — Visa and Mastercard numbers are 16 digits, Amex is 15 — so a valid-looking number should match both its scheme’s prefix and its length. Developers and merchants use this kind of check for client-side card-type detection (showing the right card logo, routing to the right payment flow) and as a first-pass format sanity check before deeper validation. This tool reads the digits you enter, detects the likely scheme from the BIN, and reports whether the length matches what that scheme expects.