Diminished Value Calculator (17c)
Estimate how much value your vehicle lost after an accident using the insurance-industry 17c formula.
Estimate only — not legal advice. This is an estimate using the widely used 17c formula, for education only — not legal advice or a guaranteed claim value. Insurers and states vary in how they assess diminished value, and an independent appraisal usually yields a higher figure than 17c. Consult a professional appraiser or attorney for an actual claim.
Diminished value is the loss in a car's resale value after it has been in an accident, even once repaired. The common 17c formula caps a base loss at 10% of the car's pre-accident value, then scales it by a damage-severity multiplier and a mileage multiplier. Independent appraisals often estimate more than 17c produces.
⚠️ Double-check important results. This is an educational estimate, not professional advice — and where it uses a rate, bracket or fee, those change over time. Verify anything you'll rely on, especially in legal, financial, tax or medical matters, and read our full disclaimer. Think a result is wrong? Tell us so we can fix it.
How to Use This Calculator
Enter your vehicle's market value just before the accident — a valuation guide for your exact year, make, model and trim is the best source. Choose the damage-severity level that matches the repairs, from severe structural damage down to minor panel work. Then enter the odometer mileage.
The calculator applies the 17c formula and returns the estimated diminished value: the resale value your car lost because its history now shows an accident, even after proper repairs.
How the Calculation Works
The 17c formula, named after a claim settlement, starts with a base loss capped at 10% of the pre-accident value. That base is then reduced by two multipliers. The damage multiplier ranges from 1.00 for severe structural damage down to 0.00 for cosmetic-only damage. The mileage multiplier steps down as the odometer rises: 1.0 under 20,000 miles, then 0.8, 0.6, 0.4, 0.2, and 0.0 at 100,000 miles or more.
Multiplying the base by both factors gives the 17c estimate. The 10% cap is why many appraisers consider 17c conservative.
17c value = (value × 0.10) × damage multiplier × mileage multiplier
Worked Example
A car worth $20,000 before the accident has a base loss of 20,000 × 10% = $2,000. Say the damage was major, giving a 0.75 damage multiplier, and the odometer reads 30,000 miles, which falls in the 20,000–39,999 band for a 0.8 mileage multiplier.
The diminished value is 2,000 × 0.75 × 0.8 = $1,200. An independent appraisal, which is not bound by the 10% cap, might value the loss higher.
Assumptions and Limitations
The 17c formula is an insurer estimating tool, not a legal standard, and its 10% base cap tends to produce conservative figures. Many states and independent appraisers use different methods that yield more. Some states also do not allow diminished-value claims against your own insurer, only a third party at fault.
Use this as a starting point, then get an independent appraisal for an actual claim.
- Uses the standard 17c formula with its 10% base-loss cap
- Independent appraisals often estimate more than 17c
- State rules on who can claim diminished value vary
- An estimate for education — not a guaranteed claim amount
Who Uses a Diminished Value Calculator
Drivers filing a claim after a crash use this to estimate a repaired car's lost resale value with the widely used 17c formula. Run it before negotiating with the at-fault driver's insurer to put a number on the diminished value they may owe. It gives you a starting figure and the reasoning behind it — useful leverage in a claim, though not a guaranteed payout.
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Open calculator →Frequently Asked Questions
What is diminished value?
It is the amount of resale value a vehicle loses after being in an accident, even after it is fully repaired, because its history report now shows accident damage that buyers pay less for.
What is the 17c formula?
It is a common insurer method that caps a base loss at 10% of the car's pre-accident value, then multiplies by a damage-severity factor (0 to 1) and a mileage factor (0 to 1) to estimate diminished value.
Is the 17c formula accurate?
It is widely used but considered conservative because of its 10% cap. Independent appraisers often calculate higher diminished value using market-based methods, which can matter in a claim or dispute.
Can I file a diminished value claim?
Often yes against an at-fault third party's insurer, but rules vary by state and many insurers will not pay diminished value on your own policy. Check your state's law and your policy.
Does mileage affect diminished value?
Yes. Under 17c, higher mileage lowers the multiplier — 1.0 under 20,000 miles down to 0.0 at 100,000 or more — because higher-mileage cars have already lost value, so the accident's added impact is treated as smaller.
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