how to identify credit card numbers
Credit Card Account Number Verification - Card Type Identification. This page provides information about identifying a credit card type from a card number's numeric range and number of digits. First digit must be a 3 and second digit must be a 4 or 7. Valid length: 15 digits. First digit must be 3 and second digit must be 0, 6, or 8. Valid length: 14 digits. Valid length: 16 digits.