If you are on a semester system, the transcript provided to colleges will usually show end of semester grades; if on a quarter system, it will show end of quarter rates, and GPA provided may be weighted or both weighted and unweighted. As to which grades are used for determining admission, it varies. Many colleges, including many public universities, will make decisions based on grades through junior year, others base on grades through first semester senior year. Moreover, many have two phases, early action or early decision and regular admission, with regular admission depending on grades through first semester senior year and early action and early decision depending on grades through junior year because decisions are issued earlier, e.g., by mid-December. As noted, some colleges like the UCs, which use grades through junior year, determine applicable GPA used for admission based on sophomore and junior year grades.
Also, those GPA’s used are not necessarily those provided by the high school. If the high school counted classes like health, word processing, PE, or vocational courses toward the GPA, the GPA will likely be recalculated to exclude those. Moreover, the college may not use the weighting system that the high school used for GPA.
Colleges do use final grades after senior year to determine if an admission decision previously given should be withdrawn.
The GPA’s you find in various places showing the middle 50% ranges or averages for the freshman class are usually not the GPA’s relied on to decide admission. Those GPA’s are typically stated to be the ranges for the freshman who actually enrolled at the college and are based on the final transcripts received after completion of high school. Depending on college, those may be stated as based on the weighted GPÅ’s of the enrolled freshman or unweighted. Those middle 50% ranges you see for enrolled students can be different from the middle 50% GPA’s of those actually admitted, both because the final senior year GPAs may differ from earlier ones actually used to determine admission, and because the college may have admitted many with high GPA’s who decided to attend elsewhere, i.e., the admission middle 50% range can actually be higher than the middle 50% ranges you see published for those who actually enrolled.