How Are Grades Calculated?

Grades are almost always calculated the same underlying way: points earned divided by points possible, sometimes combined across multiple weighted categories.

Simple point-based grades

The most basic method is points earned divided by points possible, multiplied by 100 to get a percentage. If you scored 45 out of 50 on an assignment, that's 90%.

That percentage is then mapped to a letter grade using a grading scale, which varies by school but commonly starts at 93% for an A.

Weighted category grades

Many courses instead group assignments into categories — homework, quizzes, tests, a final exam — each worth a fixed percentage of the final grade.

Your grade in each category is calculated first, then multiplied by that category's weight, and the results are added together to get your overall course grade.

Where the letter grade comes from

Once a percentage is calculated, it's compared against a grading scale table to determine the letter grade. Scales differ slightly between institutions, so always check your syllabus for the exact cutoffs your instructor uses.