Diminished value calculator

How the 17c formula works

A 2021 federal court order in Baker v. State Farm describes the steps as State Farm applies them in Georgia:

1. Base loss of value: 10% of the car's pre-loss retail value.
2. Damage severity modifier: from 0.0, no structural damage and replaced panels, to 1.0, severe damage to the structure. A 2023 paper in the NAIC's Journal of Insurance Regulation gives 0.5 for moderate damage.
3. Mileage modifier: the mileage cap minus the car's miles, divided by the cap. The cap is generally 100,000 miles, and 150,000 for some vehicles.
4. Diminished value: base loss × damage modifier × mileage modifier.

Why the result may be low

In Baker, the policyholders' appraiser argued that the formula caps the loss at 10% of value when cars can lose up to 25%, counts mileage twice, and gives nothing to cars past the mileage cap. The court did not accept that it undervalues every claim, but noted that policyholders can dispute the figure with their own evidence. The Journal of Insurance Regulation paper adds that the formula involves no inspection of the repair.

If your number looks low, an independent appraisal and listings for comparable cars are the usual way to argue for more. The full process is in our guide to diminished value claims.

Frequently asked questions

What is the 17c formula?

A method for estimating a repaired car's lost market value that came out of a Georgia class action against State Farm. It takes 10% of the car's pre-loss retail value, then multiplies it by a damage modifier and a mileage modifier, each between 0 and 1.

Is the 17c result what I am owed?

No. It is one method, used mainly by insurers in Georgia. Critics say it undervalues claims, and you can dispute the figure with an independent appraisal and evidence of what comparable cars sell for.

Why does a car with over 100,000 miles get nothing?

The mileage modifier falls to zero at the formula's mileage cap, generally 100,000 miles and sometimes 150,000. That is one of the formula's most criticised features.

Who pays a diminished value claim?

Usually the at-fault driver's insurer. Claims against your own insurer are limited outside Georgia and depend on your policy wording.

Where to go from here

Use the result as a floor for your demand, not a ceiling. Read how to file a diminished value claim and how a car accident settlement is worked out, or browse all the injury claim guides. Arhox is an independent publication, not an insurer, broker, or law firm; our editorial policy and disclaimer explain how these guides are prepared.