Retaking classes and making up high school credits has traditionally been done by taking classes during the summer. In the event a student has failed a class, many school districts will require him to attend summer school to retake that class. However, if you haven’t failed any classes but still don’t have enough credits to graduate, you can choose to enroll in summer school.
The summer school option is still a common choice for those who prefer to earn credits in a traditional classroom setting that provides a structured learning environment with a detailed course description, assignment calendar and real-life student-teacher interactions. You may also find comfort in the familiarity of reporting to your own school for classes taught by teachers you know.