The Meaning of Credit Card Numbers
If you take a close look at your credit cards, you'll probably
wonder what all those numbers stand for. Every digit actually
stands for something specific. Let's have a look at each of
those numbers in sequence.
The First Digit
Gasoline cards, department store cards and phone cards have
their own programs.
The major credit card companies operate on a standardized system
for assigning credit card numbers. The first digit in the series
will always be a 3, 4, 5 or 6. This number designates the type
of card you have. For instance, a 3 means it's a travel and
entertainment card, such as American Express or Diners Club. A 4
is Visa and Visa-branded debit cards, cash cards; a 5 is
MasterCard and MasterCard-branded debit cards, cash cards; and 6
is Discover.
The Other Numbers
American Express and Diners Club use the second digit to
identify the company. That means that Diners Club cards will
start with either 36 or 38, and American Express cards will lead
off with 34 or 37.
The remaining numbers in the series are used for other purposes,
depending upon the card type and issuer. Generally, the numbers
grouped after the opening series is the routing number of the
bank and the next group is the user's account number. The final
digit is special -- a check digit. This is a number calculated
by applying a specific formula, and it is used as a fraud check.
Look At Your Card
American Express uses digits 3 and 4 for business or personal
card type and the currency of the cardholder's country of
origin. Digits 5 through 11 are the account number. Digits 12
through 14 show the card number attached to that account. The
last digit is, of course, the check digit.
Visa uses digits 2 through 6 for the bank number. Beginning with
digit 7 and running through 12 or 15, they're the account
number, and the last number is the check digit. The number of
digits in a group may vary because Visa cards don't all have the
same number of digits. With MasterCard, the second digit through
digit 3 (to as high as 6) is the bank number. All remaining
digits, except the end check digit, identifies the cardholder's
account.
And that's it. A slightly complex system necessary to track
billions of credit cards across the globe.