A weighted GPA is a grading system that provides extra grade points for harder classes. For example, in a 4.0 grading system, an A for an US History class is worth 4 points but an A in an honors version or Advanced Placement is worth 4.5 or 5 points. This means a student could get a B in an Advanced Placement class and still have the same GPA as a student who got a A in the regular class.
Weighting is done by high schools so that students who take more challenging classes don’t suffer in terms of class ranking. Students who take only easy courses to get A’s won’t come out on top in class rank.
However, the weighted GPA isn’t very useful to college admission officers since they need to compare students from different high schools with different grading systems. Colleges will often recalculate a student’s GPA stripping any weighting as well as including only certain core classes. This provides the admissions office with a better opportunity to compare apples to apples.
This system is essentially the same as the one used by the NCAA in determining eligibility for athletes. According to their requirements, only core courses, specified for each high school, will be used to calculate GPA.