The credit card BIN numbers are the numbers that tell the bank which issued the card. These Bank Identification Numbers (BIN) are usually the first 6 digits amongst the credit card number embedded on the card. The other digits that follow the BIN are used to identify the individual account linked to the card except for the last digit. The very last digit in the credit card number is usually called the check digit which is a verification measure for security purpose. If the other credit card numbers except the last digit are put in a mathematical formula known as the Luhn algorithm they give the last digit and if not it shows that the card is invalid.

The first digit in the BIN numbers shows the general industry from which the bank issuing the card comes from. If the BIN starts with a 6 then it confirms that the card was issued by a bank or a merchandiser such as retail stores. Other industries such as airlines, travel and entertainment, other financial institutions besides banks petroleum and the government have their specific first digit on the BIN. The other five digits on the BIN are usually used to show the particular bank that issued the card. Some banks reserve some of these numbers for particular kind of credit cards such as platinum and gold cards.
The fact that the BIN numbers are six makes it possible to have millions of numbers. There are services including some found online that identifies these numbers and one can use them to search the relevant information. These numbers are usually useful since they ensure that the credit cards are segregated properly and various industries and institutions have their own numbers. As a result the use of credit cards becomes easier where in case of problems with the card it is easy to follow where the credit card came from. Furthermore, institutions issuing credit cards can also follow the cards they have issued easily.