Interchange fees are transaction fees that you pay to the card-issuing bank whenever a customer makes a purchase using a credit/debit card. Several variables are involved in calculating an interchange fee, including card type, transaction type, business type, and elements sent in the authorization and settlement messages. Interchange rates include a flat per item rate plus a percentage of the sales total. The average interchange fee equates to around 2% of the purchase amount, representing about 80% of the total cost of a transaction.

Assessment fees or network fees are charged by the card networks (e.g. Visa, MasterCard, Discover, American Express) to cover their costs of operating and maintaining their payment networks. These fees are typically charged to the acquiring bank or payment processor, which in turn usually passes them on to the merchant as part of their overall credit card processing fees. Assessment fees are charged for each transaction event like an authorization and settlement, and includes a fixed per item rate and percentage of the sales total.

These fees have grown both in the number of fees charged as well as the overall impact on the cost of payments, and sometimes are referred to as nuisance fees. Networks maintain all links to issuing banks and average about 16% of the total cost of a transaction. Here’s an exhaustive list of all network fees.