How Credit Card Validation is Processed
This validator evaluates cards for Visa, MasterCard, Discover, American Express, Diners Club, and JCB cards. The validation process checks the following:
- Luhn Algorithm: Ensures that the credit card number passes the Luhn algorithm to prove itself to be a valid credit card number.
- Major Industry Identifier (MII): The first digit of the credit card number.
- Issuer Identification Number (IIN): The next six digits after the MII.
- Personal Account Number & Checksum: The last digits include the personal account number and a checksum digit.
The validator checks these components in the following order:
- First Digit – Major Industry Identifier
- Six Digits – Issuer Identification Number
- Remaining Digits – Personal Account Number and Checksum
How to Find Bank Identification Numbers
The Bank Identification Number (BIN) is the first four to six digits of a cardholder number. It identifies both the major industry the card is primarily used with and the issuer of that card.
- The first number (MII) differentiates banking cards from other cards:
- 3, 4, 5, 6: Banking and financial industries
- 1, 2: Airline industry
- 7: Petroleum industry
- 8: Healthcare or telecommunications industries
- 9, 0: Assignment by ISO or other national standards bodies
- Common issuer IIN ranges:
- Visa: All BINs starting with 4
- American Express: BINs starting with 34 and 37
- Mastercard: BINs starting with 2221-2720 and 51-55
- Discover: BINs starting with 6011, 622126–622925, 624000–626999, 628200–628899, 64, or 65
Note: Due to the finite number of 4-6 digit BINs, issuers are starting to create 8-digit BINs. This doesn't change the length of the Primary Account Number (PAN) but affects the remaining digits used to identify specific accounts.