Diminished Value Calculator
Published by The Click Lab Agency LLC. Last reviewed September 2026. Not legal or insurance advice.
A car that has been in an accident sells for less than the same car with a clean history, even after a perfect repair. That loss is called diminished value. Many insurers start their offer from the “17c” formula, which came out of Georgia litigation against State Farm. This calculator runs that formula step by step so you can see how the insurer’s number was likely built — and where it tends to fall short.
Run the 17c calculation
How the 17c formula works
The formula has three steps. First, it caps the loss at 10% of the car’s pre-accident value; that 10% is called the base loss. Second, it multiplies the base loss by a damage multiplier from 1.00 for severe structural damage down to 0.00 when no structural damage occurred. Third, it multiplies the result by a mileage multiplier that falls from 1.00 under 20,000 miles to 0.00 at 100,000 miles and above.
Written out: diminished value = pre-accident value × 10% × damage multiplier × mileage multiplier. For a $25,000 car with moderate damage and 30,000 miles, that is $25,000 × 0.10 × 0.50 × 0.80 = $1,000.
Why the 17c number often runs low
The formula was developed on the insurer’s side, and three of its features push the result down. The 10% cap applies before any multiplier, so the result can never exceed a tenth of the car’s value no matter how badly it was damaged. The damage multiplier drops to zero when there was no structural damage, even though cosmetic-only repairs still show up on vehicle history reports. And the mileage multiplier treats any car over 100,000 miles as having no diminished value at all. None of those rules comes from a statute; they are choices built into the formula.
The alternative is a market-based appraisal: an appraiser compares actual sale or listing prices of similar vehicles with and without accident history and measures the gap. That kind of evidence is what a claims adjuster, an arbitrator, or a small claims judge is most likely to credit if you dispute the offer.
Who pays diminished value
| Situation | Can you claim diminished value? |
|---|---|
| Another driver caused the crash (third-party claim against their liability insurer) | Yes in most states, up to the at-fault driver’s property damage limit |
| Claim on your own collision or comprehensive coverage | Usually no; most auto policies do not cover it. Georgia is the main exception, where insurers must assess it (State Farm v. Mabry, 2001). |
| Michigan no-fault | Vehicle damage claims against an at-fault Michigan driver are generally limited to the “mini-tort” recovery, up to $3,000 |
| Leased vehicle | The claim may belong to the leasing company as the owner; check your lease |
Worked examples
Example 1 — Newer car, serious damage
A two-year-old SUV worth $42,000 with 15,000 miles takes a hit that bends the frame rail. 17c: $42,000 × 0.10 × 1.00 × 1.00 = $4,200 — the maximum the formula allows for this car.
Example 2 — Same damage, higher mileage
The same SUV with 85,000 miles: $42,000 × 0.10 × 1.00 × 0.20 = $840. The frame damage is identical, but the mileage multiplier removes 80% of the figure.
Example 3 — Cosmetic repair only
A sedan worth $18,000 has a replaced bumper cover and a repainted fender, with no structural work. 17c gives $0, because the damage multiplier is 0.00. If the repair appears on a vehicle history report, a buyer may still pay less; a market-based appraisal is the only way to show it.
How to dispute a low diminished value offer
- Ask the adjuster in writing how the offer was calculated and which multipliers were used.
- Get the repair invoice, which shows whether structural parts were repaired or replaced.
- Pull the vehicle history report to see whether the accident appears on it.
- Collect comparable listings or a written market-based appraisal.
- Send a written counter-offer with that evidence. If the insurer will not move, small claims court or a complaint to your state department of insurance are the usual next steps.
What this calculator does not do
It reproduces the 17c formula only. It does not value your car, check your state’s law, account for your policy’s terms, or estimate what a market-based appraisal would find. It does not add repair costs, rental or loss-of-use damages, or towing. Use the main property damage calculator for the repair and replacement side of a claim, and the diminished value guide for more on the claim process.
Sources
- State Farm Mutual Automobile Insurance Co. v. Mabry, 274 Ga. 498 (2001)
- Michigan Compiled Laws §500.3135(3)(e) (mini-tort limit)
- Your state department of insurance’s auto claims consumer guide