In most high school classes, your numerical percentage in the class determines the the letter grade you earn at the end of the term. High schools take all of your letter grades and convert them to a grade point average (GPA) scale to represent your overall academic achievement. Many high schools use a standard four-point system where all As are worth four points, all Bs three points, all Cs two points, all Ds one point and zero points for Fs.
Determine the grading scale for your classes. For example, a class might set an A at 92 percent or higher, a B at 83 percent to 91 percent, a C at 74 percent to 82 percent, a D at 65 percent to 73 percent and an F as anything below 65.
Determine the letter grade you would have earned based on your numerical grade in each class.
Determine how many points toward your GPA that class will contribute by multiplying the value of the grade you earned by the number of credits earned for the class. For example, if you received an A in a one credit class and your school uses an unweighted system, you would multiply four times one to get four points for your GPA.
Repeat Step 3 for all of your classes and take the sum of the number of points earned.
Determine the total number of credits that you have earned from all of your classes.
Divide the total number of points earned from Step 4 by the number of credits taken in Step 5 to calculate your GPA. For example, if you earned 69 points over 20 credits, your GPA would be 3.45.