Credit card (debit card) is unified, generally 16 digits, and American Express card 15 digits; Debit cards are not uniform. Generally, the minimum digit is 16, and the maximum digit of a bank card is 16- 19.

Under normal circumstances, bank cards are divided into credit cards and debit cards according to whether credit lines are granted to cardholders.

Debit cards are divided into transfer cards, special cards and stored value cards according to different functions. Debit cards cannot be overdrawn. The transfer card has the functions of transfer, cash deposit and withdrawal and consumption.

Extended data:

The bank card number consists of three parts

1, the first six digits are: Issuer ID (IIN). The first place is the major industry logo (MII). For example, the card issued by China UnionPay must start with 62; However, people who use Visa credit cards in China, their card numbers will start with 4.

2. The middle number is: personal account number identification (starting from the seventh place of the card number). The middle bit is defined by the issuing bank and generally consists of 6- 12 bits. You can use at most 12 digits.

Every bank has different rules for identifying individual account numbers. Some banks will include code information such as branches, sub-branches and savings outlets in this part. Some banks may not be so detailed and will use natural serial numbers.

3. The last digit is the check digit: use the Luhn algorithm to calculate the last digit of the credit card or debit card by the number before the card number.

References:

Baidu encyclopedia-bank card number