GrowthZone does not have the ability to apply a percentage charge to invoices to cover your credit card fees. We did investigate the option for a while, but due to the complexity of the implementation, it was decided that it was not a feature we would be able to develop:

Surcharging or the action of passing the credit card fees of a transaction onto the purchaser requires adhering to regulations that can be quite complex. The calculation of the surcharge has to take into consideration potential variables like state laws, shipping address, customer address, and the amount and the type of card used to avoid running afoul of the law and violating the merchant agreement. Several states, including Minnesota, do not allow surcharging practices at all. Trying to simplify the calculated surcharge on a given transaction by using a flat percentage rate for all transactions paid by credit card is not an option for us because it is grossly non-compliant. Given the core competencies of the software we build, we can’t logistically engineer and maintain a surcharge calculation tool accurate enough to remain in compliance. While we are not able to offer this capability at this time, there are emerging technologies in the market to offload these calculations via a third party. We are actively monitoring such services and may be able to take advantage of them when they become more compatible and feasible to integrate with our eCommerce architecture.