Diminished Value Calculator
Your car was repaired after an accident — but it is worth less now, because buyers pay less for a car with a crash on its history report. That lost value is called diminished value, and in most states you can claim it from the at-fault driver’s insurer. Enter your numbers to estimate it three ways, see exactly how the number is built, and generate a demand letter.
Your accident details
When each method applies
17c formula — the insurer baseline
Comes from a Georgia court case and is the method insurers reach for first. It starts at 10% of pre-accident value, then multiplies down for damage severity and mileage. Because it caps the starting point, it usually produces the lowest of the three numbers — treat it as the floor of your negotiation, not the ceiling.
Classic method — market-based
Estimates what the market actually takes away: a severity-based share of pre-accident value, adjusted for mileage. Use this number when you have comparable listings or a dealer quote showing the price gap between clean-history and accident-history cars like yours.
Repair-based method — share of the repair bill
Ties the loss to the repair invoice: 25% of the bill for minor damage, up to 100% for severe damage. The easiest number to explain in a demand letter, and persuasive when repairs were expensive relative to the car’s value.
Demand letter template
Fill in the blanks, generate the letter, then copy and send it to the at-fault driver’s insurer. Keep a copy of everything you send.
Negotiation playbook: when the insurer lowballs
First offers typically land at 40 to 60 percent of the real number. That is an opening bid, not a verdict. Work this checklist:
- Get their math in writing. Ask the adjuster for the worksheet behind the offer — which formula, which multipliers, which value source. Vague answers work in your favor.
- Document comparable listings. Save 3 to 5 listings of your exact year, make, model and mileage — accident-free versus accident-history. The price gap is your market evidence.
- Get a dealer trade-in quote. A written quote showing the lower offer “because of the accident history” is hard for an adjuster to argue with.
- Counter in writing with your numbers. Send the demand letter above with your 17c, classic and repair-based estimates attached. Written counters get taken more seriously than phone calls.
- Escalate if they stall. Ask for a supervisor, file a complaint with your state’s Department of Insurance, and for large gaps consider an independent appraisal ($200–$500) or a local attorney.
Diminished value law by state
General guidance only — insurance law varies by state and changes over time. Confirm deadlines and eligibility with your state’s Department of Insurance before filing.
| State | Third-party claim | First-party claim | Notes |
|---|---|---|---|
| Alabama | Usually allowed | Usually excluded | — |
| Alaska | Usually allowed | Usually excluded | — |
| Arizona | Usually allowed | Usually excluded | — |
| Arkansas | Usually allowed | Usually excluded | — |
| California | Usually allowed | Usually excluded | — |
| Colorado | Usually allowed | Usually excluded | — |
| Connecticut | Usually allowed | Usually excluded | — |
| Delaware | Usually allowed | Usually excluded | — |
| District of Columbia | Usually allowed | Usually excluded | — |
| Florida | Usually allowed | Usually excluded | — |
| Georgia | Allowed | Allowed | Home of the 17c formula (State Farm v. Mabry, 2001) |
| Hawaii | Usually allowed | Usually excluded | — |
| Idaho | Usually allowed | Usually excluded | — |
| Illinois | Usually allowed | Usually excluded | — |
| Indiana | Usually allowed | Usually excluded | — |
| Iowa | Usually allowed | Usually excluded | — |
| Kansas | Usually allowed | Usually excluded | — |
| Kentucky | Usually allowed | Usually excluded | — |
| Louisiana | Usually allowed | Usually excluded | — |
| Maine | Usually allowed | Usually excluded | — |
| Maryland | Usually allowed | Usually excluded | — |
| Massachusetts | Usually allowed | Usually excluded | — |
| Michigan | Usually allowed | Usually excluded | — |
| Minnesota | Usually allowed | Usually excluded | — |
| Mississippi | Usually allowed | Usually excluded | — |
| State | Third-party claim | First-party claim | Notes |
|---|---|---|---|
| Missouri | Usually allowed | Usually excluded | — |
| Montana | Usually allowed | Usually excluded | — |
| Nebraska | Usually allowed | Usually excluded | — |
| Nevada | Usually allowed | Usually excluded | — |
| New Hampshire | Usually allowed | Usually excluded | — |
| New Jersey | Usually allowed | Usually excluded | — |
| New Mexico | Usually allowed | Usually excluded | — |
| New York | Usually allowed | Usually excluded | — |
| North Carolina | Usually allowed | Usually excluded | — |
| North Dakota | Usually allowed | Usually excluded | — |
| Ohio | Usually allowed | Usually excluded | — |
| Oklahoma | Usually allowed | Usually excluded | — |
| Oregon | Usually allowed | Usually excluded | — |
| Pennsylvania | Usually allowed | Usually excluded | — |
| Rhode Island | Usually allowed | Usually excluded | — |
| South Carolina | Usually allowed | Usually excluded | — |
| South Dakota | Usually allowed | Usually excluded | — |
| Tennessee | Usually allowed | Usually excluded | — |
| Texas | Usually allowed | Usually excluded | — |
| Utah | Usually allowed | Usually excluded | — |
| Vermont | Usually allowed | Usually excluded | — |
| Virginia | Usually allowed | Usually excluded | — |
| Washington | Usually allowed | Usually excluded | — |
| West Virginia | Usually allowed | Usually excluded | — |
| Wisconsin | Usually allowed | Usually excluded | — |
| Wyoming | Usually allowed | Usually excluded | — |
Third-party means claiming against the at-fault driver’s insurer. First-party means claiming under your own policy — most standard policies exclude diminished value. Filing deadlines follow each state’s property-damage rules, so file within 30 to 90 days for the strongest claim.
Diminished value FAQs
What is diminished value?
Diminished value is the loss in your car’s market value after an accident, even after quality repairs. A buyer will pay less for a car with a crash on its history report, and that difference is money you can claim from the at-fault driver’s insurer.
How is diminished value calculated (17c)?
The 17c formula starts at 10% of the car’s pre-accident value, then multiplies by a damage modifier (0.25 for minor up to 1.0 for severe) and a mileage modifier (1.0 under 20,000 miles, scaling down to 0.0 over 100,000 miles). Insurers favor it because it usually produces the lowest number.
Can I claim diminished value on my own insurance policy?
Usually no. Most standard auto policies exclude diminished value for first-party claims. File against the at-fault driver’s liability coverage instead (a third-party claim). Georgia is the notable exception, where first-party claims are allowed.
Does diminished value apply to leased cars?
Yes, and it can cost you more: the leasing company owns the car, so an accident history can reduce its value at turn-in and leave you owing the difference. Check your lease agreement and talk to the lessor before you file — in some cases the lessor pursues the claim itself.
How long do I have to file a diminished value claim?
It follows your state’s property-damage statute of limitations, commonly two to six years. But claims are strongest in the first 30 to 90 days while evidence is fresh — confirm your exact deadline with your state’s Department of Insurance and do not wait.
Why is the insurer’s offer so much lower than my estimate?
Insurers typically open with the 17c formula, which caps the base at 10% of value and multiplies down from there — first offers often land at 40 to 60 percent of the real loss. Independent appraisals and comparable listings routinely support higher numbers, and that gap is your negotiating room.
Do I need a lawyer for a diminished value claim?
For most claims, no — a documented demand letter, comparable listings and a dealer quote are usually enough. Consider a licensed appraiser ($200–$500) for claims over $5,000, and a local attorney if the insurer denies the claim outright or the amount at stake is large.