Is grade 12 part of high school or college?

Given the variations in educational systems across different regions globally, I’m trying to understand the standard classification for grade 12. In some places like the United States, grade 12 is clearly the final year of high school, while in others such as certain European or Commonwealth countries, it might align with the first year of college-level education or a specialized pre-university program. This discrepancy is causing confusion, especially when comparing diplomas or transfer credits. Therefore, I need clarity: Is grade 12 universally part of high school or college, or does this depend entirely on regional educational structures?Grade 12 is part of high school. In the United States and Canada, the K-12 education system designates grades 9 through 12 as high school. Grade 12 is the senior year, where students complete their high school curriculum, earn credits toward a high school diploma, and prepare for post-secondary education or careers. After graduating from grade 12, students advance to college or university. Advanced Placement (AP) or dual-enrollment courses may offer college-level material during grade 12, but these programs operate within the high school framework and do not reclassify the student as a college attendee. Internationally, systems like the UK (where “college” often refers to post-secondary institutions) and Australia (where “college” may sometimes encompass senior secondary years) vary, but in most North American contexts, grade 12 remains exclusively part of high school. Completion of grade 12 culminates in a high school diploma, distinct from a college degree.