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Diminished Value Calculator: Estimate Using the 17c Formula
Use this calculator to see an illustrative result using the 17c formula. Some insurers use this approach when evaluating diminished value, but the result is not a vehicle appraisal, a predicted insurance offer or a determination of what you can recover.
By SettlementLift. Published · Updated .
Calculate an illustrative 17c estimate
This illustrates a published version of the 17c formula for a repaired vehicle. It does not determine coverage or legal eligibility, does not calculate a total-loss settlement, and does not use actual comparable sales, repair quality, prior accident history or every factor that affects market value. Rules vary by state, by policy and by whether the claim is against your own insurer or another driver’s.
Before relying on a number, read the diminished value claim guide and the state guides for Georgia and Florida.
Use your vehicle’s market value immediately before the accident, accounting for mileage, condition, trim and prior history. Do not use its original purchase price, loan balance or repair cost. A general valuation alone does not establish diminished value. Valuation resources: Kelley Blue Book · J.D. Power
Use your repair estimate or ask the repair shop which parts were repaired or replaced. Repair cost alone does not show whether damage was structural.
Enter your vehicle value to see an estimate.
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How the 17c formula works
The formula starts with 10% of the vehicle’s pre-accident value, called the base loss cap. It multiplies that figure by a damage factor and then by a mileage factor. The 10% figure is an assumption built into the formula, not a legal limit on what can be recovered.
Tiller v. State Farm, N.D. Ga. (2013): order describing the 17c method ↗A worked example
A car worth $30,000 before the crash has a $3,000 base loss cap. A minor damage factor of 0.25 leaves $750. At 45,000 miles the mileage factor is 0.60, so this version of the formula produces $450.
Which version this calculator uses
Court records describe the 17c method as 10% of the vehicle’s value followed by a damage modifier and a mileage modifier, with a zero mileage modifier for vehicles over 100,000 miles. The exact factor tables used here (damage 1.00, 0.75, 0.50, 0.25 and 0.00; mileage 1.00 to 0.00 in 20,000-mile bands) are the version commonly published in consumer explainers. They are not taken from a court order or regulation, and insurers may apply different modifiers. In one federal case record, the modifiers actually applied were 30% for damage and 11% for mileage.
J.D. Power: How to calculate diminished value ↗Where the formula came from
After the Georgia Supreme Court held in State Farm v. Mabry (2001) that Georgia policies covering physical loss include diminished value, a class-action order addressed how insurers would assess it. The Georgia Court of Appeals has explained that the formula is named for paragraph 17(c) of that order and that the damage modifier is a subjective judgment made by the adjuster, which can be adjusted to fit the damage.
Amica Mutual Insurance Co. v. Sanders, Ga. Ct. App. (2015) ↗What Georgia’s insurance regulator says
In Directive 08-P&C-2 (December 2008), the Georgia Insurance Commissioner stated that the Department has not endorsed any formula for diminished value, that total reliance on one formula may not be appropriate, and that insurers should not suggest a formula is endorsed or produces a definitive amount. The directive applies to insurers in Georgia; it does not set rules for other states.
Georgia Insurance Commissioner Directive 08-P&C-2 (copy hosted by Repairer Driven News) ↗Limitations of the formula
The formula does not look at comparable sales, the quality of the repair, prior accident history or every factor that affects market value. In the published table, a damage factor of zero applies when there is no structural damage or only panels were replaced, and the mileage factor reaches zero at 100,000 miles. A $0 result from those factors does not mean a vehicle lost no value; whether that loss can be claimed depends on the evidence and the applicable rules.
When this calculator does not apply
It illustrates a formula for a repaired vehicle. It does not determine coverage or legal eligibility and does not calculate a total-loss settlement. Claim rules vary by state, by policy and by whether the claim is against your own insurer or another driver’s insurer. Most states do not require insurers to pay diminished value on your own collision claim; Georgia is a notable exception.
What to do next
Evidence may support a different valuation, but it does not guarantee a higher payment.
- Ask the insurer for its calculation and the inputs it used.
- Gather repair records, the vehicle history report and relevant market evidence such as comparable listings.
- Read the diminished value claim guide and any state guidance that applies to you.
- Consider whether an independent appraisal is worth its cost given the amount in dispute.
Frequently asked questions
Is the 17c formula required by law?
No. It is named for a paragraph of a Georgia class-action order, and Georgia’s Insurance Commissioner has said the Department does not endorse any diminished value formula. It is not a legal standard or a market appraisal.
Does 17c count cosmetic damage?
In the commonly published factor table, damage with no structural repair, or replaced panels only, gets a factor of 0.00, which produces $0. Georgia’s Court of Appeals has described the damage modifier as an adjuster’s judgment that can be adjusted to fit the damage, so insurers do not all apply the table the same way. A $0 formula result does not mean the car lost no value.
Is the result what my insurer will offer?
Not necessarily. Insurers may use different inputs or modifiers, or a different method. Ask the insurer for its calculation and the inputs it used.