No, if you have a Visa or Master card, as long as your card has the currency of US dollars, you will not be overcharged if you use US dollars, unless your card does not have a US dollar account, for example It has dual currencies of RMB and Euro, so when you swipe US dollars, they will be converted into Euros for your account. Visa will charge you a currency conversion fee of 1%, and Master will charge 1.1%.