The highest possible GPA depends on the grading scale used by a school.
- On an unweighted GPA scale, the highest GPA a student can earn is 4.0, which corresponds to straight A's in all classes.
- On a weighted GPA scale, which accounts for course difficulty by giving extra points for honors, AP, or IB classes, the highest GPA can range typically from 4.5 to 5.0. In some cases, unconventional systems may report GPAs above 5.0, but for most high schools, 5.0 is the usual ceiling.
- Weighted scales give extra points for advanced classes, for example, an A in an AP class might be worth 5.0, while a regular A is worth 4.0.
So, the highest GPA possible in many U.S. high schools with weighted scales is often 5.0, whereas in unweighted systems it's 4.0.