The interest-free repayment period is from the monthly settlement date (i.e. billing date) to one month (up to 365,438+0 natural days) before the repayment due date of the following month (generally 20-30 days). The due repayment date of the bank is determined as the 20th day after the monthly settlement date (bookkeeping date), that is, the longest interest-free period is 5 1 day and the shortest interest-free period is 20 days.