The 25th day after the billing date. According to the query on the official website of 51 Renpindai, we learned that the billing date of 51 joint credit card is the 15th of each month, and the repayment date is the 25th day after the billing date. 51 Credit Card is a credit card management and loan service provider that mainly provides users with online credit cards. management, credit card application and consumer financial services. The company also independently developed the iCredit big data risk control system to ensure platform security.