Identify the student's letter grades for each course in a particular semester. Find the corresponding grade points using the conversion table. For example: Biology "B" = 3; English "C+" = 2.33; History "A" = 4; and Math "B+" = 3.33.
Add the total number of grade points for the completed courses. For the above example, 3 + 2.33 + 4 + 3.33 = 12.66.
Add up the total number of credit hours for the courses completed. For example, 3 credits of Biology + 2 credits of English + 3 credits of History + 2 credits of Math = 10 credit hours.
Multiply the grade points by the number of credit hours for each class. For example, Biology 3 x 3 = 9; English 2.33 x 2 = 4.66; History 4 x 3 = 12; and Math 3.33 x 2 = 6.66. Next, add these numbers together: 9 + 4.66 + 12 + 6.66 = 32.32.
Divide the total by the number of credit hours completed for the semester. For example, 32.32 / 10 = 3.23 GPA.