Car Diminished Value Calculator

Your car has been repaired and looks fine, but it is no longer worth what it was. The moment an accident lands on its history report, buyers offer less. That lost resale value is called diminished value, and in most states you can ask the at-fault driver's insurer to pay for it.

Car's value before the accident

$

Check KBB, Edmunds or NADA for a car like yours, in the condition it was in before the crash.

Mileage at the time of the accident

miles

The odometer reading on the day of the crash.

How bad was the damage?

Severe structural damageFrame or unibody bent, major parts replaced Major structural and panel damageStructural repairs plus several body panels Moderate structural and panel damageSome structural work, a few panels Minor structural and panel damageLight structural work, mostly panels No structural damageCosmetic only: bumper, paint, trim

Repair cost optional

$

From your repair estimate or final invoice. Helps you sanity check the damage level you picked.

Calculate diminished value

How this diminished value calculator works

Most insurers that agree to pay diminished value start with a method called 17c. It gets its name from a paragraph in a 2001 Georgia Supreme Court case, State Farm v. Mabry, and it has since become the default opening move across the industry. Our calculator runs the same math, step by step:

1. Start with the market value of your car right before the crash.
2. Take 10% of it. This is the "base loss," and it is a hard cap. Under 17c your car can never lose more than 10% of its value, no matter what.
3. Multiply by a damage factor from 1.00 for severe structural damage down to 0.00 for cosmetic damage only.
4. Multiply by a mileage factor from 1.0 for under 20,000 miles down to 0 at 100,000 miles or more.

Damage level	Multiplier
Severe structural damage	1.00
Major structural and panel damage	0.75
Moderate structural and panel damage	0.50
Minor structural and panel damage	0.25
No structural damage (cosmetic)	0.00

Mileage	Multiplier
0 to 19,999	1.0
20,000 to 39,999	0.8
40,000 to 59,999	0.6
60,000 to 79,999	0.4
80,000 to 99,999	0.2
100,000 and up	0

Every formula and assumption behind this calculator is listed in our methodology, and our editorial policy explains how we check and update it.

A worked example

Say you drive a car worth $30,000. It has 35,000 miles, and the crash caused moderate structural and panel damage.

• Base loss: $30,000 x 10% = $3,000
• Damage factor: $3,000 x 0.50 = $1,500
• Mileage factor: $1,500 x 0.80 = $1,200

So 17c says your car lost $1,200. Now ask yourself: if you were buying a used $30,000 car, would you knock only $1,200 off the price after seeing structural damage on the Carfax? Most people would want a lot more. That gap is exactly why we call the 17c number a floor, not a fair answer.

Why 17c usually comes in low

We want to be upfront about this, because the insurer probably won't be. The 17c method was not built from resale data. It has three features that pull the number down:

• The 10% cap. Real losses on newer or higher-end cars with structural repairs can go well past 10%.
• Zero at 100,000 miles. A 2020 truck with 105,000 miles still sells for real money, and an accident report still hurts that price.
• Zero for cosmetic damage. A bumper and paint job can still show up on a history report and make buyers nervous.

None of this means the calculator is wrong. It means you now know the number the adjuster is likely to start from, and why it is fair to push back.

What can change your diminished value

• An independent appraisal. A licensed diminished value appraiser compares your car with real listings and sales. If your car is newer, low mileage or valuable, an appraisal often lands well above 17c and gives you something concrete to send the insurer.
• Who you claim against. A third-party claim against the at-fault driver's insurer is the normal route. A first-party claim against your own policy depends heavily on your policy wording and your state.
• Your state. Georgia requires insurers to consider diminished value in some first-party claims. Other states are less friendly. See your state page for details.
• Quality of the repair. Poor repairs, mismatched paint or non-original parts make the loss bigger, and they are worth documenting with photos.

Three more examples

Car	Value	Damage	Miles	17c result
Compact sedan	$18,000	Minor structural and panel	52,000	$270
Family SUV	$42,000	Major structural and panel	18,000	$3,150
Pickup truck	$36,000	Severe structural	88,000	$720

Look at the pickup. It had the most serious damage of the three, yet its 17c number is small because of the mileage. A buyer shopping for a $36,000 truck would almost certainly knock off far more than $720 after seeing frame damage on the history report.

Who can claim diminished value

• You, against the at-fault driver's insurer. This is the most common and most successful route, called a third-party claim.
• You, against your own insurer. Possible only if your policy covers it, which many do not. This is called a first-party claim.
• Owners of leased or financed cars. Usually yes, but read diminished value after a lease or loan first, because the lender or leasing company may have a say.

Mistakes that cost people money

• Waiting too long. Claims are easier while the repair is recent.
• Accepting the first 17c number without checking the inputs.
• Using the wrong value. Always use the value before the crash, for your exact trim and options.
• Not keeping the repair invoice. It is your best evidence of the damage level.
• Forgetting to ask at all. Many adjusters will not bring it up.

How to claim diminished value

1. Get your repair records. Ask the body shop for the final invoice and the list of parts replaced.
2. Find your pre-accident value on Kelley Blue Book or Edmunds, using the condition your car was in before the crash.
3. Run the calculator to see the 17c floor.
4. Consider an appraisal if the gap between 17c and what you think you lost is large.
5. Send a written demand to the at-fault driver's insurer. Our demand letter generator has a diminished value version that fills in your numbers.

Read the full walkthrough in What Is Diminished Value and How to Claim It.

Frequently asked questions

What is a diminished value claim?

It is a request for the value your car lost because it now has an accident history, even after it was properly repaired. You usually make it against the at-fault driver’s insurance company.

How is diminished value calculated?

Insurers usually start with the 17c formula: 10% of the car’s pre-accident value, multiplied by a damage factor and a mileage factor. Independent appraisers use real market data instead, which often gives a higher number.

Can I claim diminished value if the accident was my fault?

Usually not against the other driver. Some policies allow a first-party claim with your own insurer, but many exclude it. Read your policy or ask your agent.

Does diminished value apply to a leased car?

Yes, the loss still exists, and your lease company may charge you for it at turn-in. Check your lease contract and our guide on diminished value after a lease or loan.

Is there a deadline for a diminished value claim?

Yes. It follows your state’s deadline for property damage claims, which is often two to six years. Do not wait that long, though. Claims are easier while the repair is recent.

Is the 17c formula required by law?

No. It is a method insurers commonly use as a starting point. You are free to present your own evidence, like an appraisal or comparable sales.

Does diminished value apply to older cars?

It can, but the amount is often small for older, high mileage cars. Under 17c, cars with 100,000 miles or more get zero, although real buyers may still pay less for a car with an accident record.

Can I use this calculator for a motorcycle or RV?

The 17c formula was designed for cars and light trucks. You can run the numbers, but treat the result as a rough guide and consider a specialist appraisal.