The length of bank card numbers varies depending on the type and card-issuing bank. Debit cards include 19-digit card numbers in most cases, but debit cards of China Merchants Bank and China Construction Bank have 16 digits, and Bank of Communications have 17 digits. As for credit cards, that is, credit cards, the card numbers of all banks are unified to 16 digits.

Specifically, each bank is as follows: China Construction Bank: Deposit card numbers have 16 or 19 digits, and credit card numbers are fixed at 16 digits. Agricultural Bank of China: The debit card number is 19 digits, and the credit card number is also 16 digits. Industrial and Commercial Bank of China: Debit card number is 19 digits, credit card number is 16 digits. Bank of Communications: The card number is 17 digits for debit cards and 16 digits for credit cards. Minsheng Bank: Debit card and credit card numbers are both 16 digits.

The composition rules of the card number include: the first digit is the industry identification code, which is usually determined by the card issuer, and the middle digits can be composed of 6 to 12 digits, including the bank’s internal branch or outlet code; the last digit is The check code uses the LUHN algorithm to ensure the accuracy of the card number through a specific calculation method.

In general, the length of bank card numbers varies depending on the type and issuing bank. The number of digits in debit cards and credit cards is different, and the last digit of the card number is verified through a specific algorithm. . If you need to check the specific card number length, you can usually get accurate information from the bank's official website or the services provided by the bank.