Transform your letter grades to their point value. Most colleges use a four-point scale and add 0.33 for pluses and subtract 0.33 for minuses. For example, an A- would be 3.67 and a C+ would be 2.33.
Compute the grade points earned per class by multiplying the point value equivalent by the credit hours for the class. Not all college classes award equal credit. For example, for a four credit hour class that you got a B+ in, multiply 4 by 3.33 to get 13.32.
Add the points earned from each of your courses to find the total number of points you've accumulated.
Add the number of credit hours earned in all of your classes together to find your total number of credit hours earned.
Divide your total points accumulated by the total hours of courses taken to find your college GPA. For example, if you earned 199.8 points over 60 credit hours, divide 199.8 by 60 to get a GPA of 3.33.