A total loss is an arithmetic decision, not an aesthetic one. Cars that look catastrophic get repaired and cars that look repairable get written off, and the difference is the relationship between the repair cost and the vehicle’s value.
The calculation
Insurers compare the estimated cost of repair, usually including anticipated supplements, against the actual cash value of the vehicle immediately before the loss, less its salvage value. When repair costs exceed a threshold percentage of that value, the vehicle is declared a total loss.
Why it surprises people
Because value falls faster than repair costs. Modern cars carry sensors, cameras, aluminum panels and complex lighting, so even moderate front-end damage runs into real money. An eight year old car with a low market value reaches the threshold quickly, which is why a car that still drives can be written off.
Actual cash value is where to focus
The valuation is the part worth attention, because it is the part most often too low. It should reflect your vehicle: its trim level, options, condition, mileage and the local market. If the comparable vehicles used are lower spec, higher mileage or from a different market, that is a legitimate challenge.
How to challenge it
Provide listings for genuinely comparable cars nearby. Document service history, recent tires, a recent major service or new components. Get an independent appraisal if the numbers are far apart. Put it in writing.
Keeping the vehicle
You can usually retain a total loss vehicle, with the salvage value deducted from the settlement. The car then carries a salvage or rebuilt title, which affects future value, insurance and inspection. It sometimes makes sense; it should be a considered decision rather than a sentimental one.
Do not forget the rest
Check whether your policy covers a rental while it is settled, and whether you can claim diminished value if the repair goes ahead instead.
Related: insurance claim repair and estimating.