Semester hours, credit hours, and class hours are generally the amount of hours you spend in class per week during the semester. Ex: a four hour class, you attend four days a week for an hour a day. Expect to spend two hours reading for each hour of class material, and another hour per week studying and organizing your notes. So multiply your semester hours x4 or so for an estimate of how many hours you'll work 1L. I have 16 hours, which = 64 hours/week of law school.