Here's how the ACS poses the question:
No schooling completed
Nursery school
Grades 1 through 11
12th grade—no diploma
Regular high school diploma
GED or alternative credential
Some college credit, but less than 1 year of college
1 or more years of college credit, no degree
Associates degree (for example: AA, AS)
Bachelor’s degree (for example: BA. BS)
Master’s degree (for example: MA, MS, MEng, MEd, MSW, MBA)
Professional degree beyond bachelor’s degree (for example: MD, DDS, DVM, LLB, JD)
Doctorate degree (for example, PhD, EdD)
https://www.census.gov/topics/educat...ent/about.html