Your billing date is 13 every month, and the repayment date is 1 next month. It means that after you swipe your card, the bank will issue a bill, and before the bill, that is, 13, you have to pay it back before 24: 00 of next month 1, so there is no interest, that is, you have wasted the bank's money. If you don't pay in full, you will have to charge interest. From credit card to repayment, the interest is five ten thousandths per day. Pay back according to the minimum repayment amount, and the interest will be calculated as usual, but the bank recognizes that you are trustworthy and not overdue. Swipe your card after 13, and charge it to the bill of 13 next month, and return it before 1 next month.