Legal analysis: credit cards have articles of association, and the calculation method of overdue penalty (used to be late payment fee) is stipulated in the articles of association of credit cards, and the total interest can exceed the principal. There is an agreement when handling credit cards, and the agreement is signed in accordance with the articles of association. The cardholder shall abide by the articles of association and the agreement, and the overdue period shall be handled according to the articles of association.

Legal basis: Civil Code of People's Republic of China (PRC).

Article 673 Where the borrower fails to use the loan according to the agreed purpose, the lender may stop issuing the loan, recover the loan in advance or terminate the contract.

Article 674 The borrower shall pay interest at the agreed time limit. If the time limit for paying interest is not stipulated or clearly stipulated, and cannot be determined according to the provisions of Article 510 of this Law, if the loan period is less than one year, it shall be paid together with the loan; If the loan term is more than one year, it shall be paid at the end of each year; if the remaining term is less than one year, it shall be paid together with the loan.

Article 676 If the borrower fails to repay the loan within the agreed time limit, it shall pay the overdue interest in accordance with the agreement or the relevant provisions of the state.