About the Diminished Value Calculator
This diminished value calculator estimates how much a vehicle’s market value drops after it has been in an accident and repaired, using the “17c” formula that many insurers apply to third-party diminished value claims. A car with an accident on its history report usually sells for less than an identical car without one, even when the repairs are perfect; that gap is the diminished value.
It is meant for drivers who were not at fault and are filing a claim against the other driver’s insurer, and for anyone wanting a quick benchmark before getting an independent appraisal. Enter the car’s pre-accident market value (from a pricing guide or dealer appraisal), choose how severe the damage was and enter the odometer reading.
The 17c method caps the starting loss at 10% of the car’s value and then scales it down for damage severity and mileage — cars with 100,000 miles or more get nothing. Critics argue it understates real losses, especially for newer, low-mileage or luxury vehicles, so treat the result as the insurer’s likely opening figure rather than the true market loss. Rules on who can claim diminished value vary by state.
With the default inputs, the estimated diminished value (17c) is $1,200.00. Change any value above to recalculate instantly.
How to use the diminished value calculator
- 1Look up the car’s pre-accident market value in a pricing guide or from a dealer.
- 2Choose the damage severity that matches the repair estimate.
- 3Enter the odometer reading at the time of the accident.
- 4Read the 17c diminished value and compare it with an independent appraisal.
Formula and method
The 17c formula starts by capping the possible loss at 10% of the car’s pre-accident market value. That base is multiplied by a damage factor — 1.00 for severe structural damage, 0.75 major, 0.50 moderate, 0.25 minor and 0 for no structural damage — and by a mileage factor that falls from 1.0 under 20,000 miles in 0.2 steps for every 20,000 miles, reaching 0 at 100,000 miles.
The formula takes its name from paragraph 17c of a Georgia court order in a class-action case against an insurer, and it is now widely used by insurers. It is a simplified rule, not a market study; appraisers instead compare the selling prices of similar vehicles with and without accident histories.
- Market value
- Value of the car just before the accident
- Damage multiplier
- 0 to 1 depending on structural damage severity
- Mileage multiplier
- 1.0 under 20,000 miles down to 0 at 100,000+
Worked examples
$30,000 car, moderate damage, 35,000 miles
The base loss is 10% of $30,000 = $3,000. Moderate damage applies 0.50 and 35,000 miles applies 0.8, so the 17c diminished value is $3,000 × 0.5 × 0.8 = $1,200.
Nearly new $45,000 SUV with severe damage
With severe structural damage and under 20,000 miles both multipliers are 1, so the full 10% cap applies: $4,500, leaving an estimated post-repair value of $40,500.
High-mileage car with minor damage
The $2,000 base loss is cut to a quarter for minor damage and to a fifth for 85,000 miles, leaving only $100 — an example of how sharply 17c reduces claims on older cars.
Frequently asked questions
What is the 17c formula for diminished value?+
It multiplies 10% of the car’s pre-accident value by a damage multiplier (0 to 1) and a mileage multiplier (1.0 under 20,000 miles down to 0 at 100,000 miles). It originated in a Georgia insurance class action and is commonly used by insurers to value claims.
Can I claim diminished value from my own insurance?+
Usually you claim diminished value from the at-fault driver’s insurer. Most policies exclude first-party diminished value claims, though a few states allow them in limited cases. Check your state’s rules and your policy.
Is the 17c formula fair?+
Critics say the 10% cap and steep mileage reductions understate real market losses, especially for newer and luxury vehicles. An independent appraisal comparing sale prices of similar cars is often used to negotiate a higher amount.
How long do I have to file a diminished value claim?+
Diminished value claims against another driver generally follow your state’s statute of limitations for property damage, often two to six years, but it is best to file soon after repairs while records are fresh.
Results are estimates for educational purposes and are not financial advice. Rates, fees and terms vary — confirm with your lender or a licensed advisor before making decisions.