Diminished Value Calculator
A diminished value calculator estimates how much resale value your car lost after an accident, even once the repairs are finished and the vehicle looks and drives the way it did before. This tool applies 17c, the formula many insurers use when they evaluate a diminished value claim, and it returns a range rather than a single figure. The low end is the strict 17c result and the high end is 17c before its most contested step, the mileage deduction. It is an educational illustration of an insurance industry formula, not an appraisal of your vehicle and not a statement of what any claim will pay.
This calculator applies 17c, a formula used in the insurance industry, for educational purposes only. 17c is contested, it is not a legal standard, and it commonly produces figures below what an independent appraisal finds. Nothing here is an appraisal, a valuation of your vehicle, or legal advice. Actual diminished value depends on your vehicle, your repair records, an independent appraisal, and the law that applies to your situation. Consult a licensed attorney and a qualified appraiser about your circumstances.
This calculator applies 17c, a formula used in the insurance industry, for educational purposes only. 17c is contested, it is not a legal standard, and it commonly produces figures below what an independent appraisal finds. Nothing here is an appraisal, a valuation of your vehicle, or legal advice. Actual diminished value depends on your vehicle, your repair records, an independent appraisal, and the law that applies to your situation. Consult a licensed attorney and a qualified appraiser about your circumstances.
Question 1 of 6
What was your vehicle worth just before the accident?
Enter the pre-accident market value in dollars. A resale value guide or a recent appraisal is a common starting point.
What Is the 17c Formula?
The 17c formula is the diminished value method most insurers apply: it caps the loss at 10 percent of the vehicle's pre-accident market value, multiplies that cap by a damage severity factor, then multiplies again by a mileage factor that falls to zero at 100,000 miles. The name comes from paragraph 17c of a 2001 Georgia settlement involving State Farm, and carriers across the country adopted the method from there.
In practice the formula runs in three steps. Step one sets a ceiling of 10 percent of pre-accident market value. Step two multiplies that ceiling by a damage factor, which insurers read off the repair estimate. Step three multiplies the result by a mileage factor, which is 1.00 under 20,000 miles and drops in steps to 0.00 at 100,000 miles.
17c is a claims handling shortcut, not a valuation standard and not a rule of law. An independent appraiser measures the actual difference between what the car would have sold for undamaged and what it sells for with an accident on its record, which is a different exercise and can land well above or below the 17c figure.
- The 10 percent figure is a ceiling built into the formula, not a legal cap on what a claim can recover
- The mileage step is the piece owners dispute most often, because market value already reflects mileage
- An independent appraisal is the usual way to put a different number in front of an adjuster
Why Insurers Use 17c and Where It Falls Short
Carriers like 17c because it is fast, consistent, and produces a defensible looking number from three inputs an adjuster already has. It is public and explainable, which is why this calculator uses it, but the same simplicity is the source of most complaints about it.
The common criticisms are that the 10 percent ceiling is arbitrary, that the mileage multiplier double counts mileage the market value already accounts for, and that a zero multiplier at 100,000 miles wipes out the claim entirely on an older vehicle that may still have lost real resale value. Owners who disagree with a 17c figure generally respond with an independent appraisal, dealer trade-in quotes, or comparable listings rather than arguing the formula itself.
- Ask the adjuster in writing which damage factor was applied and why
- A written appraisal from a licensed appraiser is the most common counterweight to a 17c figure
- Trade-in quotes from dealers on the same year and model can show the real market reaction
How to Document a Diminished Value Claim
Documentation is what moves a diminished value discussion, since the loss is not something an adjuster can see on the repaired car. The core record set is the repair estimate and final invoice showing every part and operation, photographs of the damage before repair, the police report or incident record establishing fault, and proof of the vehicle's pre-accident condition such as service records or a recent listing.
On top of that record set, most owners add something that shows the market reaction: an independent diminished value appraisal, written dealer trade-in offers, or comparable listings of the same year, model, and mileage with and without an accident history. A vehicle history report showing the accident on the record is often the simplest illustration of why a buyer would pay less.
- Keep the itemized repair invoice, since it identifies aftermarket parts a resale inspection can flag
- Photograph the damage before any repair work begins if that is still possible
- Get trade-in offers in writing rather than relying on a verbal number
Diminished Value in California and Arizona
In California, diminished value is generally pursued as a third party claim against the at fault driver's insurer, meaning the carrier for the person who caused the crash rather than your own. Whether your own policy covers it depends on the language of that policy, and filing deadlines apply, so the timing is worth checking early.
Arizona also generally allows a diminished value claim against the at fault driver's carrier. In both states what can actually be recovered turns on the evidence, particularly an independent appraisal, and on proving who was at fault. Deadlines for filing differ by state and by the type of claim, and this tool does not track them for your situation.
Neither state treats 17c as binding. It is one method an insurer may use to open a negotiation, not a limit written into the law.
- A third party claim goes to the at fault driver's insurer, not your own carrier
- Fault matters: a diminished value claim generally depends on someone else being responsible for the crash
- Filing deadlines apply in both states, so check them before assuming there is time
About this topic
Why This Calculator Shows a Range
Diminished value is not a fixed number sitting inside a vehicle. It is the gap between what a car would have sold for with a clean history and what it sells for once an accident appears on its record, and that gap moves with the buyer, the model, the region, and how the repair was documented. Because of that, this calculator shows a range rather than a single figure: the low end is the strict 17c result after the mileage deduction, and the high end is the same calculation before that deduction, which is the step owners contest most often. A range is an honest way to show how much the outcome depends on which version of the formula an adjuster applies.
What 17c Cannot Account For
The formula reads three numbers and ignores everything else. It does not know whether the repair was done well, whether structural work was documented in a way a future inspection will surface, whether the model holds value unusually well or unusually poorly, or whether the local market for that vehicle is tight. It also does not know what an independent appraiser would find. That is why a 17c figure is a starting point for a conversation rather than a conclusion, and why owners who disagree with one generally bring outside evidence rather than arguing about multipliers.
Diminished Value Is Separate From Repair Costs
Repair costs and diminished value answer two different questions. Repair costs cover putting the vehicle back together; diminished value covers the resale value the accident history takes away even after a complete, high quality repair. A car can be repaired perfectly and still sell for less, because the accident shows up on a vehicle history report and buyers price that in. Because they are separate, settling the repair portion of a claim does not automatically settle the diminished value portion, and it is worth reading any release carefully before signing so you understand what it covers.
Frequently Asked Questions
Diminished value is the resale value a vehicle loses because it has an accident on its record, even after a complete repair. Two identical cars, one with a reported accident and one without, generally do not sell for the same price. That difference is the loss a diminished value claim tries to address.
Insurers commonly apply 17c: cap the loss at 10 percent of the pre-accident market value, multiply by a damage severity factor, then multiply by a mileage factor that reaches zero at 100,000 miles. Independent appraisers instead compare what the vehicle would sell for with and without the accident history, which can produce a very different figure.
In California a diminished value claim is generally made as a third party claim to the at fault driver's insurer after the repairs are complete. Owners usually submit the repair invoice, damage photographs, the police report, and an independent appraisal supporting the amount claimed. Filing deadlines apply, and a licensed attorney can explain how they apply to your situation.
Proof generally comes from outside evidence rather than the formula. Common items are an independent diminished value appraisal, written trade-in offers from dealers, comparable listings of the same year and model with and without accident history, the itemized repair invoice, and the vehicle history report showing the accident. The stronger that record, the more there is to discuss with an adjuster.
It depends on the state, the policy, and who was at fault. Many carriers will consider a third party diminished value claim against the at fault driver's coverage, while first party claims under your own policy often depend on specific policy language. Insurers also frequently deny these claims on older or high mileage vehicles, which is where 17c produces a zero result.
Arizona generally allows a diminished value claim against the at fault driver's insurer. As in California, what can be recovered turns on the evidence supporting the amount and on establishing fault for the crash. Deadlines apply, and the specifics of any individual claim are worth reviewing with a licensed attorney.
That depends on the numbers and the effort involved. An independent appraisal has a cost, and 17c produces small or zero figures on older, high mileage, or lightly damaged vehicles. Newer vehicles with structural damage and low mileage tend to show the largest gap. Running the range here first is one way to see whether the amount justifies the process.