Are UIUC and UC San Diego acceptance rates comparable for judging admission chances?

No. UIUC’s and UC San Diego’s overall acceptance rates are only a rough indicator and should not be used as a direct comparison of your admission chances. At UIUC, selectivity can vary dramatically by college and major, with computer science and certain engineering programs far harder to enter than the university-wide figure suggests. At UC San Diego, the UC application process, California-resident applicant base, and competition for capped majors create a different admissions context.

UIUC is more useful to evaluate through your intended program. Applicants apply to a specific major or academic unit, and preparation in relevant coursework matters especially for capacity-constrained fields. A student applying to a less restricted UIUC program should not assume they face the same odds as an applicant to CS, engineering, business, or another high-demand program.

UC San Diego is better assessed as part of the UC system’s comprehensive review process. It is test-free in admissions, considers applicants in the context of their high school opportunities, and receives a very large number of applications from California students as well as out-of-state and international applicants. Your residency status and intended major, particularly whether it is capped, can meaningfully affect how to interpret UCSD’s published overall rate.

For a realistic comparison, look first at whether your major is selective or capped at each university, then compare your transcript strength, advanced coursework, grades in math and science where relevant, and activities tied to your academic interests. Treat each school’s overall rate as background information, not a personalized estimate.