Keeping accurate count of your semester credit hours can help you graduate on schedule. Semester hours, or semester credit hours, reflect the academic work expected during a typical 15-week semester. One semester credit hour is calculated as two hours of independent work and one hour of class lecture each week. The average full-time 15-credit hour semester would require roughly 45 hours of work per week, with different classes varying in total semester hours based on the number of credits they award.