No, it is calculated based on the natural month.

The final repayment of CCB credit card is calculated based on the statement date. The 20th day after the bill date is the final repayment date. Then the poster’s bill date is the 19th of each month. If pushed forward 20 days, the final repayment date will be the 8th (31st day of the new month) or the 9th ( Every 30 days of Xiaoyue). For example, for a bill on 5/19, the final repayment date is 6/8; for a bill on 6/19, the final repayment date is 7/9; for a bill on 2/19, the last repayment date is 3/11 (in February it is 28 days).