How can I find Columbia University class sizes by major?

Columbia does not publish a simple official chart of average class size by major, so the best way to do this is to use Columbia’s course directory and department websites to sample actual courses in the majors you’re considering. That will give you a much more accurate picture than the university-wide student-faculty ratio, especially because intro courses in economics, computer science, and biology can be much larger than upper-level seminars in the humanities. You can also use Columbia’s Common Data Set for overall distribution of class sizes, but it will not break those numbers down by department.

Then check each department’s undergraduate program page. Some departments list typical course formats, seminar offerings, or sample pathways, which helps you interpret what you see in Vergil. For example, a department may have a few very large gateway courses but still offer many small major seminars once students move beyond the intro level.

For school-wide context, look up Columbia’s Common Data Set and the section showing how many classes enroll under 20 students, 20 to 49, and so on. Use that only as a baseline, then rely on Vergil plus department contacts for major-specific comparison.