A 3.9 GPA is right in California Institute of the Arts's admitted middle-50% GPA range of 3.62–3.92.
That puts you in the typical admitted band. It's a solid baseline, but GPA alone won't get you in — the rest of your profile carries real weight here.
A GPA is the single biggest academic factor, but it's necessary, not sufficient — especially at a 32.3%-acceptance school like California Institute of the Arts. Your test scores, course rigor, extracurriculars, essays, and any standout achievements all move the number. The estimate above assumes typical scores and rigor; your real odds depend on your full profile.
Estimates are CDS-based and for a typical applicant. Run your full profile for your real, calibrated odds.