Applying to state-side Graduate programs with European degree(s) So I'm a bit confused because the structure of higher education is different in America than it is here. In the States the typical undergraduate degree (for example in physics) is around 4 years. From what I heard, most students who end up getting a doctorate go straight to "grad school" after their undergrad degree. However in Europe, according to the Bologna Process , the 3 year Bachelors is usually followed by a 1-2 year Masters program before enrolling in a Phd program.

The question is, how are these 2 systems of education compatible? Let's say I want to do my physics Phd in the U.S., would I need to have both my Bachelors and Masters degrees before applying to a "Grad School", or would a bachelors suffice?
Usually a BSc would suffice. This is because PhDs in the US typically contain 2-3 years of lectures, coursework and exams before you do any research. This is the equivalent of doing a separate Master's (and indeed, many students pick up a Master's degree on the way to the PhD, almost by default). In the European system, PhD students start research from day one, so most will have a Master's degree already.

You could consider emailing the graduate admissions people at the universities you're interested in, to find out more about entry requirements specific to your own case.