The final repayment date of BOC credit card is the 20th day after the bill date, and the full repayment before the final repayment date is interest-free. The accounting date is 23rd (fixed), that is to say

The bill was generated on September 23rd, recording the transactions from August 24th to September 23rd, and the final repayment date was the 20th day after September 23rd, namely 10. 13.

Generate a bill 10.23, and record the transactions during September 24th-10.23. The final repayment date is the 20th day after 10.23, that is,1.12.

And so on.

Obviously, the shortest interest-free period is 20 days (9.23 brush, 10. 13 times) on the billing date, and the longest interest-free period is 50 days (9.24 brush,12 times) on the first day after the billing date. It should be noted that credit card consumption has an interest-free period, and cash withdrawal has no interest-free period.