The basic rule: repair cost vs. actual cash value
Insurers compare the estimated cost of repairs to the vehicle's actual cash value (ACV) — what your car was worth the moment before the crash. If repairs approach or exceed a set percentage of ACV, the carrier declares a total loss. The exact percentage varies by insurer and state, but it's commonly in the 70–80% range. Below that, repair is usually the path; above it, you'll likely get a total-loss settlement instead.