To calculate grade and percentages you must know how many points each grade is worth, for example: A=4, B=3, C=2, D=1, F=0. After you have added together all of your grades you then divide them by the number of classes you have taken. If you have taken 5 classes earning 1A 3B's and 2 C's you add 4+3+3+3+2=14. Now divided 15/5= 3. The number 3 is equal to the B letter grade; therefore, you
. would have a B average or a GPA of 3.0.