Learn your grades for a particular grading period. If you are in high school, ask your teachers for your grades or wait until you receive your report card. If you are in college, you can ask your professor for your grades or wait until they are posted.
Correspond a letter grade to a number on a 4-point scale. Typically, an "A" is worth 4 points. A "B" is worth 3 points, a,"C" 2, a "D" 1 and an "F," or failing grade, is worth 0 points. If your high school or college awards + or - letter grades, find out the point equivalent of those grades. For example, at some schools an "A-" is worth 3.7 points and a "B+" is worth 3.3.
Add the points you earned for each class. For example: You have five classes and earned an "A" (4 points), "B-" (2.7), "C+" (2.3), "A-" (3.7) and a "B" (3). Add the points. 4+2.7+2.3+3.7+3. Points earned: 15.7.
Divide the points (15.7) by the number of classes (5) to determine your GPA. In this case, the GPA is 3.14, which is between a "B" and "B+."