Credit card numbers are comprised of 16-digits (Visa, Master and Discover), and 15-digits for American Express (AMX). Others may have 14-digits (Diners Club) or 12 to 19-digits for Maestro cards. The credit card numbers are divided into Issuer Identification Number (IIN) and Account Identification Number (AIN). IIN used to be known as Bank Identification Number (BIN), and the first 6 to 8-digit numbers represents IIN. By looking at the IIN, you'll be able to find card type, brand, and bank who issued the credit card.