How many numbers are in a credit card?
Visa begins with 4 16 digits
Master " " 5 "
Discover " " 6 "
Amex " " 3 15 digits
The first digit of a credit card indicates the type of credit card you are holding. Three is American Express, 4 is a Visa card, 5 is MasterCard, and 6 is Discover. The numbers that follow identify the issuing institution; indicate the type of card, whether debit or credit; and are numbers assigned to you by the issuing institution.