The installment fee for a credit card is calculated based on factors such as the installment amount, number of installments, and interest rate. Calculation methods and interest rates may vary from bank to bank, but the basic principles are similar. The following is the general calculation method:

1. Calculate the installment fee: The credit card installment fee varies depending on the bank, the number of installments and personal credit rating. Normally, the more installments, the higher the handling fee. For specific handling rates, you can consult the bank or check the bank's official website.

2. Calculate the handling fee for each period: Multiply the installment amount by the handling rate for each period to obtain the handling fee payable for each period. For example, if the installment amount is 10,000 yuan, the number of installments is 12, and the handling fee per period is 0.6, then the handling fee per period is 10,000*0.6=60 yuan.

3. Calculate the total handling fee: Multiply the handling fee per period by the number of installments to get the total handling fee. For example, if the installment amount is 10,000 yuan, the number of installments is 12, and the handling rate for each installment is 0.6, the total handling fee is 60*12=720 yuan.

It should be noted that credit card installment fees may have some additional fees, such as early repayment fees, overdue fees, etc. In actual operation, it is recommended to consult the bank or read the credit card terms carefully to understand the detailed fee calculation method and related regulations.

In short, the calculation method of credit card installment fee is to multiply the installment amount by the fee rate of each installment, and then multiply by the number of installments to get the total fee. When handling credit card installment business, you must fully understand the handling fee calculation method and relevant regulations, and rationally choose the number and amount of installments to avoid unnecessary losses.