There are 3 levels of study in the US Higher Education System. The first one is the Undergraduate level. In the undergraduate level, students only study in a 2 year course where they will earn Associate degree which is usually a 2 years prerequisite course. After this, they have a choice to pursue and earn a 4 year Bachelor’s degree. Most students study in a community college for the undergraduate level then transfer to a four-year university or college.

The second level is the Graduate in Pursuit of a Master’s Degree. If you want to advance in your career, you may consider to take a graduate study. Graduate programs in pursuit of a master’s degree usually take one to two years to complete. Earning this degree is usually mandatory if you aim for higher-level positions. Earning a PHD degree may take longer for international students. 

The third level is the Graduate in Pursuit of a Doctorate Degree. 

There are graduate schools that require a master’s degree as a prerequisite to earn a PHD while there are schools that allow students to directly take doctorate without earning a master’s degree. It may take three or more years to earn a PHD degree. Earning a PHD degree may take longer for international students.