Diminished Value Calculator

Diminished value is the drop in your vehicle's market value after an accident, measured after the repairs are finished. A repaired car with an accident on its history report can sell for less than an identical car with a clean history, and that difference is the loss. How much a given car loses depends on the car and its market, which is why it has to be documented with market evidence rather than assumed.

Some insurers use the 17c formula: 10% of the pre-accident value, multiplied by a damage severity modifier and a mileage modifier. State Farm's use of it is described in federal court records (Baker v. State Farm, M.D. Ga. 2021). Other insurers may use their own methods. Whatever method the insurer uses, you can respond with evidence of your car's actual pre-accident and post-repair market values.

It is a simplification. It cannot produce more than 10% of pre-accident value, the damage modifier is picked by the insurer's adjuster, and in State Farm's version the mileage modifier reaches zero at the maximum-mileage setting. Georgia's Insurance Commissioner told carriers that total reliance on one formula "may not be appropriate given the subjective nature of the claim." Policyholders have sued arguing it produces artificially low figures; in the other direction, a Georgia appeals court held that one insurer's use of it was a reasonable basis to contest a claim. For your claim, the useful question is whether the 17c number matches your car's documented market loss.

It depends on your policy wording and your state's courts. Florida's Supreme Court held that a collision policy promising to repair or replace with "like kind and quality" does not owe diminished value after a first-rate repair (Siegle v. Progressive Consumers Ins. Co., 819 So. 2d 732 (Fla. 2002)). Georgia's Supreme Court reached the opposite result on State Farm's policy (Mabry, 274 Ga. 498 (2001)). Read your policy's payment-of-loss and limit-of-liability sections. If another driver caused the accident, a claim against that driver's insurer is a separate route.

Against the at-fault driver, the deadline to file a lawsuit is set by each state's statute of limitations. Florida: 2 years for an action founded on negligence (Fla. Stat. § 95.11(5)(a)), for accidents after March 24, 2023; earlier accidents fell under the prior four-year period (Laws of Fla. ch. 2023-15, § 28). Wisconsin: 3 years for property damage from an accident involving a motor vehicle (Wis. Stat. § 893.52(2)). Minnesota: 6 years for injuring personal property (Minn. Stat. § 541.05, subd. 1(4)). North Dakota: 6 years for injuring goods or chattels (N.D. Cent. Code § 28-01-16(4)). South Dakota: 6 years for injuring goods or chattels (SDCL § 15-2-13(4)). A claim under your own policy runs on the policy's terms and your state's contract rules; in Wisconsin, an action on a motor vehicle insurance policy has 3 years (Wis. Stat. § 893.43(2)). These are deadlines to sue, so present your claim to the insurer well before them.

A well-documented diminished value claim includes: (1) your vehicle's pre-accident market value and how you arrived at it; (2) its post-repair market value, ideally from a written independent appraisal; (3) the complete repair invoices, showing the parts used and the labor; (4) the police or accident report; (5) photos of the damage before repairs; (6) the vehicle history report showing the accident; and (7) a written demand that states the amount and attaches the evidence.

The 17c formula is a claim-handling method an insurer chooses to use, and it came out of Georgia litigation. Georgia's Insurance Commissioner has said the Department has not endorsed a particular formula or method. You are not required to accept an insurer's offer. If you disagree with a 17c figure, answer it with evidence of your car's actual market values.

Many owners present the claim themselves, with a written demand and supporting evidence. Questions about your legal rights, or whether to file suit, belong with an attorney licensed in your state. Our role is the appraisal: a written valuation report of your vehicle's pre-accident and post-repair market values that you can put in front of the insurer.