Convert each individual grade to its LSAC equivalent using the table linked in the "Resources" section. If, for example, you have an "A+," a "B" and a "C-" on your transcript, your LSAC equivalents will be 4.33, 3.0 and 1.67, respectively.
Weigh each grade for the number of credit hours it represents. For example, if you earned the "B" and "C-" in classes worth four credit hours, but the "A+" in course that was only worth two, the "A+" will only hold half weight in your overall calculation. Multiply each grade point by the number of credit hours it represents, add them together, then divide the number by the total number of credit hours: (4.33 x 2) + (3.0 x 4) + (1.67 x 4) = 8.66 + 12 + 6.68 = 27.34/(2 + 4 + 4) = 2.734.
Remove any grades of "withdraw" or "incomplete" from your calculation. According to law school resource "Prelaw Handbook," LSAC does not include these values in its calculations.