In the United States, a student in a high school or university earns credits for the successful completion of each course for each academic term. The state or the institution generally sets a minimum number of credits required to graduate. Various systems of credits exist: one per course, one per hour/week in class, one per hour/week devoted to the course (including homework), etc.
 

In high schools, where all courses are usually the same number of hours, often meeting every day, students often get a half credit per course per semester. This is formally known as a Carnegie Unit. After a typical four-year run, the student needs 24 to 28 credits to graduate (an average of 5¼ to 6 courses per quarter). Some U.S. states have only three years, with 16 to 18 credits required.
 

In college or university, students typically receive credit hours based on the number of "contact hours" per week in class, for one term; formally, Semester Credit Hours. Regardless of the duration of the course (i.e. a short semester like summer or intersession) and depending on the state or jurisdiction, a semester credit hour (SCH) is 15-16 contact hours per semester.

Most college and university courses are 3 Semester Credit Hours SCH or 45-48 contact hours. To provide students with the minimum 45-48 contact hours while accounting for holidays, college start dates, etc., many courses will have 50 or more contact hours. Otherwise, a Monday (or Monday/Wednesday/Friday) course may have only 42 contact hours, while a Tuesday (or Tuesday/Thursday) course may have 48 contact hours.
 

Because students are generally expected to spend three hours outside class studying and doing homework for every hour spent in class[citation needed], 15 SCH is a full course load. Many colleges consider 12 SCH a minimum full-time load for financial aid and other purposes. Some schools set a flat rate for full-time students, such that a student taking over 12 or 15 credit hours will pay the same amount as a student taking exactly 12 (or 15). A part-time student taking less than 12 hours pays per credit hour, on top of matriculation and student fees.
 

Credit for laboratory and studio courses as well as physical education courses, internships and practicums is usually less than for lecture - typically one credit for every two to three hours spent in lab or studio, depending on the amount of actual instruction necessary prior to lab.
 

College and university faculty typically teach 4 courses or 12 SCH. This varies however, with technical and community college faculty loads sometimes higher. University faculty with a heavier emphasis on research frequently receive reduced course loads in lieu of research, in the form of "course releases" or "load lifts." While faculty workloads are almost universally based on the number of SCH taught, faculty teaching in technical "clock hour" programs in technical and community colleges have workloads that more closely resemble high school teaching.
 

To figure a grade-point average (GPA), the grade received in each course is subject to weighting, by multiplying it by the number of credit hours. Thus, a "B" (three grade points) in a four-credit class yields 12 "quality points". It is these which are added together, then divided by the total number of credits a student has taken, to get the GPA. Transfer credits may not be counted in the GPA.
 

Some courses may require a grade higher than that which is considered passing. In this case, a grade of "D" will still add to the total number of credits earned (unlike an "F"), but the course will not be counted toward graduation requirements until it is retaken and completed with at least a "C".
 

Credit by examination is a way of receiving course credit without taking the course. This grade often shows as a "K" on a transcript, however it carries no credit hours, and therefore has no effect on the GPA. This also means that a student often must take other classes instead, to meet minimum hour requirements. (This still benefits the student, because he or she can learn something new and useful, instead of repeating what is already known.)
 

Various types of student aid require students to take and complete a minimum number of course credits each term. Schools often require a minimum number or percentage of credits be taken at the school to qualify for a diploma from that school—this is known as a residency requirement. DANTES and College Level Examination Program are two programs that offer college bound students credit by examination.