The longest interest-free period for CCB credit cards is 50 days, and the shortest is 20 days, that is, the repayment date is the 20th day after the bill date. The billing date is the 27th, and the repayment date is the 20th day after the billing date, that is, around the 17th (because it spans a month, there are 30 and 31 days, so it is not certain), that is to say:

Card purchases made from September 28th to October 27th will be debited on October 27th, and the payment can be made before November 16th.

Consumption by card from October 28th to November 27th will be debited on November 27th, and the payment can be made before December 17th.

So, if you swipe your card on the bill day, the interest-free period will be the shortest, only 20 days (swipe the card on October 27, and repay on November 16). If you swipe your card on the bill date, the interest-free period will be the longest, with 50 days (swipe the card on October 28 and repay on December 17).