Calculate your GPA.

Assign each grade in your transcript a number from the chart at the left.

Add them all up.

Divide by the total number of classes (yes, count the total classes, including ones you failed and got zeroes for).

Note: Honors classes have bonus points on A's and B's (5 and 4, respectively).  AP classes have bonus points on A's, B's, and C's (5, 4, 3)