A lot of regulations depend on your status in the PhD program, such as G3, G4, or G5. If you're following the typical progression in the PhD program, your status in each year will be:

• Year 1: G3 or G4
• Year 2 and 3: G4
• Year 4 and 5: G5

Specifically:

• G3 if you are currently in year 1 of the PhD and have completed less than 24 credits of graduate-level course work, including courses taken prior to joining the PhD program.
• G5 once you have been advanced to candidacy (this usually happens in the summer between year 3 and year 4).
• G4 if you are neither G3 nor G5. If you entered the PhD program with a completed master’s degree, you are usually classified as G4 from the start.

+) Now you must be wondering what G1 and G2 mean. Those are for master’s students:

• G1: First-year master's or advanced certificate student who has completed fewer than 24 graduate credits at Stony Brook. Requires 12 credits per semester for full-time status.
• G2: Advanced master's or certificate student who has completed 24 or more graduate credits at Stony Brook. Requires 9 credits per semester for full-time status.