Calculate how many credit hours each course you're taking this semester is worth, using your schedule, transcripts or the university's course catalog. Add these hours, and write the number on a scrap piece of paper. Label this number, "attempted credit hours."
Obtain a copy of your school's handbook, and search for the point value of each letter grade. Schools assign a point value to each grade, in order to make calculating GPA easier. Because schools use different grading scales, the numbers vary from school to school. On a 4.0 scale, which many schools use, an A is worth 4 points.
Obtain a copy of your grades for this semester, and copy the course name, grade, and number of credit hours attempted into your notebook. Now, using the student handbook from the step above, place in parenthesis next to each grade, the number of points it is worth.
Multiply the number of points, based on your letter grade and the number of credit hours for each course. This means, if you have an A in a three-credit hour course on a 4.0 scale, you would have 12 total points.
Add the point values from the last step. Write this number on a scrap piece of paper, and label it, "points earned."
Divide the number of points you received, by the number of credit hours you took this semester. The resulting number is your GPA.