Almost all banks will provide the Credit Cards with some interest free period on purchases.Interest free period is the time for which the bank won't charge any interest on your purchases. Suppose, your credit card has interest free period of 50 days. It is not that, you will get 50 interest free days on your every purchase. It will be calculated based on your billing date. Here is how it will be calculated.Suppose, your credit card billing date is 2nd July. This bill includes the purchases from 2nd June to 1st July. You have to pay that amount on or before 22nd July, as your credit card has 50 days interest free period. Here, the things you purchased on 2nd June got 50 interest free days but the things you bought on 1st July got only 20 interest free days.So, the interest free period is the maximum time for which banks won't charge any interest on your purchases.