In the US, it's typically a 4 year undergrad, 2 year masters, and a ~5-7 year PhD depending on the program itself. From what I understand, while there are some classes you take as a PhD student, a majority of your work is doing research
For PhD students, the masters is integrated into the 5 years they spend doing their PhD. They are expected to take courses as a "pre-candidate" and do primarily research after they pass their qualifying exams and become candidates.
This is usually true but not always. I attended an economics program with a terminal master’s offering, and we spent a year and a half as master’s students before moving on to PhD work.
Just for completeness sake. In the EU a bachelor's is 3 years, a master 1 or 2 (2 being the standard) and a PhD 3-5 years. It depends on the country, so it's possible to get 3+2+5.
