Change each of your letter grades for all classes you have taken into numerical equivalents. For example, if you want to calculate your mean college GPA, include all college classes you have taken. An A converts to a 4, a B to a 3, a C to a 2, a D to a 1 and an F to a 0.
Figure the value of each of your classes by multiplying the number of credit hours earned for the class. For example, if you have an A in a one-credit class, multiply 4 by 1 to get 4. If you got a D in a three-credit class, multiply 1 by 3 to get 3.
Add the points earned in each class taken.
Divide the number of points earned in all classes by the total credit hours taken to find your mean GPA. For example, if you earn 320 points over 106 credit hours, divide 320 by 106 to get a mean GPA of 3.02.