Find out how much the semester's final exam is weighted. In many high schools, this grade accounts for 20 to 25 percent of the total grade.
Subtract the worth of the final exam from 100, then divide this number by 2. This is how much each quarter grade is worth.
Multiply each quarter grade and the final exam by its percentage of the final grade.
For example, if a student earned an 86 percent the first quarter, an 88 percent the second quarter, and got a 92 on the final exam, which is worth 20 percent of his final grade, you would set up the following three equations:
0.40 * 86 = 34.4
0.40 * 88 = 35.2
0.20 * 92 = 18.4
Add the totals. This is the semester grade.
34.4 + 35.2 + 18.4 = 88. The student earned an 88 percent for the semester.
Assign each quarter class the number of grade points appropriate to your letter grade in that class. If you are a transfer student, check with your academic adviser or the registrar's office to see if you need to use the new school's GPA scale.
For example, a class in which you earned an A- and 4.00 grade points at College A may only transfer as an A- and 3.67 grade points at University B, which uses a different grading system.
Multiply the quarter units you earned in that class by the grade points.
For instance, if you earned an A (4.00) in a four-quarter unit class, you earned 16 grade points.
Multiply this number by 0.667, keeping only the first two digits after the decimal point. Do not round. This is your adjusted "semester" GPA for that class.