Vertical · Diminished value · Updated 2026

Diminished value calculator

Even a perfect repair doesn't erase an accident from your car's history — a buyer typically pays less for it. This calculator uses the "17c" formula, a convention from a 2001 Georgia court case, not a national standard. Read the limitations below before you rely on the number.

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Uses the "17c" formula — a Georgia court-case convention, not a national standard. See the warnings below the result for what this number does and doesn't capture.

Pre-accident vehicle value ($)

Mileage at time of accident

Damage severity

Estimated diminished value

$800

Base value (10% of pre-accident value): $2,000
Damage multiplier: 0.50
Mileage multiplier: 0.80

This is an estimate using one common variant of the 17c formula, not a guarantee or an official appraisal.

Where the "17c" formula comes from — and where it falls short

The name comes from where the formula appeared in the record of State Farm Mutual Automobile Insurance Co. v. Mabry, a 2001 Georgia class action. A trial court had ordered State Farm to develop a method for assessing post-repair diminished value, and 17(c) was the result. It is not a state or federal statute, and not a nationally standardized method — different insurers and appraisers use different variants of it.

The formula: 10% of your vehicle's pre-accident value, multiplied by a damage-severity factor (0.00 for cosmetic-only up to 1.00 for structural damage), multiplied by a mileage factor that typically steps down from 1.00 under 20,000 miles to 0.00 at 100,000+ miles.

Can you actually file this claim?

It depends on your state and who you're claiming against. A third-party claim — against the at-fault driver's insurer — is more widely available than a first-party claim against your own insurer, but both vary significantly by state. Georgia, where the 17c formula originated, is one of the more established jurisdictions for diminished value claims. Check your state's current rule before filing, since this is an area where the law genuinely differs from state to state.

A certified, independent vehicle appraisal — not this calculator or the insurer's own internal number — is what actually carries weight if the claim is disputed. Use the calculator above to get a rough sense of scale before deciding whether an appraisal is worth the fee.

Q&A

Frequently asked questions

01 What is diminished value?

The drop in your vehicle's resale value after it's been in an accident and repaired, even if the repair is perfect. A buyer typically pays less for a car with a reported accident history than for an identical car with none — that gap is the diminished value, and some states let you claim it separately from the repair bill.

02 What is the "17c" formula?

A method for calculating diminished value that takes its name from where it appeared in the record of a 2001 Georgia court case, State Farm v. Mabry. It's not a state or federal standard — it's a convention some insurers and appraisers use, and others use different variants. Formula: 10% of your car's pre-accident value, multiplied by a damage-severity factor and a mileage factor.

03 Can I file a diminished value claim in every state?

No. Some states only recognize first-party diminished value claims (against your own insurer) in limited circumstances or not at all; third-party claims (against the at-fault driver's insurer) are more commonly available but still vary by state. Georgia, where the 17c formula originated, is one of the more established jurisdictions for these claims. Check your state's rule before filing.

04 Is the 17c formula calculator accurate?

It's a starting point, not an official number. Because there's no single standardized formula, insurers routinely offer less than a professional appraisal would support, and courts have questioned whether the mileage multiplier double-counts depreciation already reflected in the vehicle's pre-accident value. A certified vehicle appraiser's report carries more weight than this calculator's output in an actual claim or dispute.

05 Do I need an appraisal to file a diminished value claim?

Not always required, but it strengthens the claim significantly. An independent, certified appraisal gives you a defensible number instead of relying on the insurer's own (often low) internal calculation. For higher-value vehicles or contested claims, the appraisal fee is usually worth it relative to the increase in the settlement.