• Yes, Mastercard and Visa are the most accepted, but check the signs before enter a shop/restaurant. Paypass is also widely used.
• Still, it is a good idea to change some forints, because in some museums, ticket offices, kiosks, bars etc. only cash is accepted.
Practical information
What is the currency in Hungary?
Hungarian currency is called forint. One Euro is cca. 300 forints.