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Diminished Value Calculator — what your car lost after the crash
This diminished value calculator estimates how much resale value your car lost simply because it was in an accident, even after perfect repairs. It uses the 17c formula that insurers recognise, so you can put a figure on a diminished value claim before the adjuster names one.
Enter your vehicle's pre-accident value, its mileage band and how severe the damage was, plus your state. The tool estimates how much market value your car lost after the repair — your diminished value claim.
What this estimates. Diminished value is the gap between what your car was worth before the crash and its lower market value after repair — money you can often claim from the at-fault driver's insurer. This is a property-damage tool, not an injury tool: it values your car, not your injuries.
Use it as a diminished value calculator to estimate your car's lost value after an accident, even on a vehicle that looks fully repaired.
See also: This figure covers the car only. If anyone in it was hurt, that is a second claim against the same insurer — value it with the personal injury settlement calculator.
Real data
Where the 17c diminished value formula comes from
The 17c formula is not science — it is a courtroom shortcut. It comes from State Farm Mutual Automobile Ins. Co. v. Mabry, a 2001 Georgia Supreme Court case where 25,000+ drivers claimed lost resale value after repairs. To handle the class at scale, the court adopted a generic formula capped at 10% of the car's value. Insurers now apply it as a default — which is exactly why first offers are often low.
Source: State Farm Mut. Auto. Ins. Co. v. Mabry, Supreme Court of Georgia (2001). The 17c formula is an insurer estimate, not a binding valuation, and first offers are frequently below a car's true lost value — use the calculator above and consider an independent appraisal.
The method
How the 17c diminished value formula works
Start from 10% of your car's value, then apply a damage multiplier and a mileage multiplier.
Base value cap
Start with 10% of your car's pre-accident market value (KBB/NADA).
Damage multiplier
0.00–1.00 for severity — structural damage scores high.
Mileage multiplier
Higher mileage means less diminished value.
Estimated DV
Cap × damage × mileage = your claim estimate.
Appraisal
An independent appraisal supports a higher figure if the insurer lowballs.
Worked example
How to calculate diminished value, step by step
The 17c formula is three multiplications and nothing else. Run it by hand once and you will know immediately whether an insurer's offer was built the same way.
Step 1 — the base loss cap. Take the pre-accident value of your car and multiply it by 0.10. That 10% is the ceiling the formula puts on the whole loss, no matter how bad the crash was. A car worth $30,000 the day before gives a base of $3,000.
Step 2 — the damage modifier. Multiply the base by the severity band the repair falls into: 1.00 for severe structural or frame damage, 0.75 for major damage to structural panels, 0.50 for moderate panel work, 0.25 for minor panel and paint, and 0.00 for cosmetic-only. This is a step function, not a slope, which is why the wording on your repair invoice matters so much. Moderate damage: $3,000 × 0.50 = $1,500.
Step 3 — the mileage modifier. Multiply again by the band your odometer falls in: 1.00 under 20,000 miles, 0.80 to 40,000, 0.60 to 60,000, 0.40 to 80,000, 0.20 to 100,000, and 0.00 above 100,000 miles. A car at 45,000 miles: $1,500 × 0.60 = $900.
What the answer is and is not. $900 is what the 17c method produces, and it is the number most adjusters start from. It is not a market appraisal. The formula pays nothing at all above 100,000 miles and nothing for cosmetic-only damage, which is exactly where an independent appraisal tends to disagree with it. If your car is newer, rarer or has an unusually severe entry on its history report, an appraisal will often land higher than 17c does — and the appraisal is the document you would have to produce to argue for the difference.
Filing
Filing a diminished value claim with the at-fault insurer
It is a separate claim from the repair, and it is not automatic: the repair is paid on the estimate, the lost value has to be asked for. Four things decide whether the ask lands. Fault: you are claiming against the other driver's property-damage liability coverage, which means their insurer only owes you if their driver was at fault. Timing: file after the repair is complete, because the completed repair invoice is what classifies your damage band in step 2 above. Evidence: the pre-accident value from a recognised guide, the repair invoice, and photographs of the damage before repair. The history report: an accident entry on a vehicle-history report is the mechanism that makes the loss real to a future buyer, so a claim on a car with no entry is much harder to argue.
If the figure the insurer returns is materially below the one you calculated, the usual next step is an independent appraisal, which typically costs a few hundred dollars. That cost is only worth carrying when the gap you are arguing about is comfortably larger than it — run the calculator at your own damage band and at the band the insurer used, and the difference between the two tells you whether it is.
Adjust for your state
Diminished value by state
Eligibility and how insurers handle 17c vary by state — check before you file.
Case law clearly supports diminished value, e.g. Georgia.
Third-party DV claims are accepted but insurers push back; an appraisal helps.
Some states limit recovery or first-party DV; check before filing.
Insurers recognize 17c but are not bound by it; negotiation matters.
This is a question of whose insurer you are asking, not one of negligence. Nearly every state lets you claim it from the at-fault driver's insurer. Far fewer let you claim it from your own insurer under collision coverage — Georgia is the clearest exception, following Mabry v. State Farm, the case the 17c formula itself comes from. Work out which of the two situations you are in before you file, because it decides who you are allowed to ask.
Questions
Diminished value claim FAQ
A standard method: 10% of pre-accident value × a damage multiplier × a mileage multiplier. It is an estimate insurers recognize, not a guaranteed payout.
Often yes — from the at-fault driver's insurer, because a repaired car with an accident history still sells for less.
Usually it is a third-party claim against the at-fault driver; first-party claims depend on your policy and state.
Pre-accident value (KBB/NADA), repair invoices, and an independent appraisal if needed.
Newer, higher-value, low-mileage cars with structural or frame damage lose the most.
Run it again with the damage severity moved one step
The 17c damage modifier is a step function, so the distance between "moderate" and "severe structural" is not gradual — it is the largest single jump in the whole formula. Move it one step and you see exactly what the repair classification is worth to you. No contact details are asked for at any point.
Open the calculator