The highest GPA possible varies by country and grading scale. In the U.S., the unweighted GPA scale typically tops out at 4.0, while a weighted GPA can exceed 4.0—sometimes reaching 5.0 or higher with advanced courses like AP or IB. Some schools use a 100-point scale instead. Ultimately, the “highest GPA” depends on the system used, but 4.0 or 5.0 are common maximums in the U.S.