Does eighth grade classes affect your GPA?

Yes, eighth-grade classes affect your high school GPA, but only if your high school awards credit for those classes. Many high schools allow students to earn high school credit for certain eighth-grade courses, particularly advanced classes like algebra or a foreign language. If your high school does this, and you get a grade in the eighth grade class that counts towards high school credit, then that grade will absolutely be a part of your high school GPA. If not, it won't be included.