If you're attempting to determine what your grade point average will be after a given semester, you can visit the iCampus portal. Log in, click on the MyInfo tab, and enter your PIN. Please be aware that the "Estimate my GPA" calculator does not calculate course repeats.
Under the Status heading, you will see a link to "Estimate my GPA." Here you will find not only the GPA calculator, but additional important information regarding how calculations are made, and what different designations exist for withdrawl and credit/no credit.