A number that is unique and that identifies a credit card account. Each credit card that is issued around the world will have a unique number, and no two banks will ever issue a card with the same number. The account number is personal to the owner and this information is necessary when making online purchases where the cardholder is not present.
The credit card account number will be made up of a certain amount of digits which will be displayed on the front of the card with a security number on the rear face of the card. Although the vast majority of credit cards are now pin enabled to avoid other people using stolen cards, it is vital that you keep your details private and report your card stolen or missing if you lose it.
Though most people aren’t aware of it, the numbers on a credit card aren’t just random. There is a definite order and the numbers give very specific information about the card and the issuer.
The very first number of every credit card is an industry identifier that tells which industry issued the credit card.
Cards beginning with a 1 or 2 are issued by the airline industry. If they are travel and entertainment cards (like American Express and Diners Club) they’ll begin with a 3. All Visa credit cards start with a 4 and all Mastercards begin with a 5. The number 6 is used for Discover credit cards.
Once the industry is determined the card number goes on to identify the issuing bank. The next six numbers of the card identify which bank issued the card and is responsible for payments.
After the first seven numbers comes your own personal account number, which is comprised of all the remaining numbers, except the final number.
That final number is known as the checksum and it is set using the Luhn formula, which was patented by IBM scientist Hans Peter Luhn in 1960. The Luhn formula uses all the other numbers on your card to verify that it is a valid card number.
This formula and the checksum digit are primarily used to protect against input errors such as entering the wrong card number during the checkout process on an ecommerce site. If the digits you enter are off by even one, the checksum digit will be able to determine that the numbers you entered don’t add up properly based on the Luhn formula, and you’ll be informed you entered an invalid number.
So, now you know that there’s far more than you probably expected included in those digits on a credit card.