Discuss BIN number formats

[Good Carder]

What is a BIN Number?​

A Bank Identification Number (BIN), also referred to as the Issuer Identification Number (IIN), is the initial sequence of digits on a payment card, such as a credit, debit, or prepaid card. It serves as a unique identifier for the issuing bank or financial institution and follows standards set by ISO/IEC 7812. Traditionally, BINs consisted of the first six digits of the card's Primary Account Number (PAN), but recent updates have expanded them to eight digits or more to accommodate the growing number of issuers. The full PAN can range from 8 to 19 digits in length, with the BIN forming the leading portion, followed by an account identifier and a check digit (validated via the Luhn algorithm).

BINs are crucial in the payments ecosystem for verifying card authenticity, routing transactions, detecting fraud, and enabling merchants to apply custom logic like risk screening or regional restrictions. They do not reveal sensitive personal information but provide high-level details about the card's origin and type.

BIN Format and Structure​

The BIN format is structured as follows:

• Major Industry Identifier (MII): The first digit of the BIN, which categorizes the type of issuing institution.
• Issuer Identification: The remaining digits (up to 7 more in an 8-digit BIN) specify the exact bank, financial institution, or network.

Here's a breakdown of common MII values and their associated categories:

MII Digit	Issuer Category	Examples of Card Brands/Networks
0	ISO/TC 68 and other industry assignments	Various specialized uses
1	Airlines	Airline-specific cards
2	Airlines and future assignments	Airline or reserved
3	Travel and entertainment	American Express (starts with 34 or 37), Diners Club
4	Banking and financial	Visa (starts with 4)
5	Banking and financial	Mastercard (starts with 51-55 or 2221-2720)
6	Merchandising and banking	Discover (starts with 6011, 622126-622925, 644-649, or 65)
7	Petroleum	Fuel cards
8	Healthcare and telecommunications	Telecom or healthcare cards
9	National assignment	Government or national-specific cards

This table is derived from standard industry assignments, which can evolve but remain largely consistent.

The overall card number format under ISO/IEC 7812 is:A BBBBB CCCCCCCCCCCC D

• A: MII (1 digit)
• BBBBB: Remaining BIN digits identifying the issuer (5-7 digits, making the total BIN 6-8 digits)
• CCCCCCCCCCCC: Account identifier (up to 12 digits)
• D: Luhn check digit (1 digit for validation)

For instance, a Visa card might have a BIN like 412345, where '4' is the MII for banking, and the rest identifies the specific issuer (e.g., a particular bank).

Evolution to 8-Digit BINs​

Historically, BINs were fixed at six digits, but due to the depletion of available numbers amid the rise of fintech and more issuers, the ISO updated the standard in 2017 to allow for eight-digit BINs. By 2022, major networks like Mastercard and Visa mandated the use of eight-digit BINs for new assignments, while legacy six-digit ones remain valid. This change increases the pool of available identifiers but requires updates to payment systems, fraud detection tools, and merchant processes to handle the longer format without disrupting transactions.

Examples of BIN Formats by Major Networks​

• Visa: Always starts with 4 (MII=4). Example BIN: 412345 (six digits) or extended formats like 41234567 (eight digits).
• Mastercard: Starts with 51-55 (older) or 2221-2720 (newer ranges). Example: 512345 or 222100.
• American Express: Starts with 34 or 37 (MII=3). Example: 341234.
• Discover: Starts with 6 (MII=6), often 6011 or 65. Example: 601123.

These formats help in quick identification during transactions, but BINs can also indicate card level (e.g., classic, gold, platinum) or type (debit vs. credit) in more detailed lookups.

In summary, BIN formats provide a standardized way to encode essential payment card details, balancing simplicity with the need for scalability in a global financial system. If you're interested in specific BIN ranges or tools for validation, public databases and APIs exist for legitimate uses like development or compliance.