* The institution: Different colleges and universities have different credit systems. Some might award 4 credits for a full trimester course, others might use a different number (e.g., 3, 5, or more).
* The course level: Advanced or upper-level courses might be worth more credits than introductory courses.
* The course intensity: A lab-intensive science course might be worth more credits than a lecture-only humanities course, even if they meet for the same number of hours.
* The length of the trimester: A longer trimester might have courses worth more credits.
To find out how many credits a specific trimester class is worth, you must consult the course catalog or syllabus for that particular institution and course.