Surcharging
Adding a clearly disclosed fee to credit-card transactions to offset processing costs, subject to network rules.
Surcharging keeps a single listed price and adds a disclosed fee when a customer pays by credit card. It offsets processing costs but carries specific registration, notification, and ceiling requirements set by the card networks.
Surcharging rules vary by card type and jurisdiction and change over time, so it should be implemented by a processor who sets it up correctly and keeps it current — not bolted onto checkout ad hoc.