There are two situations for Bank of China to write off a credit card. Specific analysis:

1. If the user does not owe any balance when writing off a Bank of China credit card, there will be no interest.

2. If the user has not paid off the card bill after canceling the card, interest will be calculated in installments, starting from the transaction recording date based on the actual amount owed and the actual amount owed. The overdraft interest is calculated based on the number of days. The overdraft interest rate is 0.5% of the daily interest rate, and compound interest is calculated on a monthly basis.