The maximum interest-free period is 50 days. But I want to remind you that this does not mean that you can get 50 days of interest-free by swiping your card on any day. If you want to achieve the longest interest-free period, you need to swipe your card on the day of your billing, because the card swiping on that day will be recorded on the next working day, so the billing date of the money will become the next month. Only in this way can you achieve the theoretical limit. Maximum interest-free period. Don’t think that all your money is for a 50-day interest-free period. Be sure to look at the bill.