Draw a table with as many rows as the number of courses you are taking in the current year and five columns. Write the name of every course in the first column of the table.
Write the current letter grade for each course. You can calculate this by averaging any exams and coursework grades you have already received. Convert your letter grade by its numerical equivalent: A=4, B=3, C=2, D=1 and F=0. Write the numerical equivalent in the next column.
Write in the next column the credits for each course. Multiply your numerical grade by the number of credits of that course. Write the result in the last column. This step ensures your average grade is weighted by the importance and difficulty of the course.
Add all the values of the last column and divide by the number of courses. This is your GPA.