# What is my car’s diminished value?

Estimates a car’s diminished value after an accident by the 17c formula: 10% of its pre-accident value, times a damage multiplier and a mileage multiplier.

- Page: https://www.acalculator.org/finance/diminished-value-calculator
- JSON spec: https://www.acalculator.org/finance/diminished-value-calculator.json
- Version: 7c393663ce4d

## Default answer

Example with the default inputs (Value before the accident $30,000.00, Damage Moderate structural and panel damage (0.50), Mileage 45,000, Mileage multiplier 20,000-mile steps): Diminished value by the 17c formula: $900.00 (10% base $3,000.00 × 0.5 × 0.6).

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| val | Value before the accident | The car’s market value just before the accident, from a pricing guide or an appraisal. |
| dmg | Damage | How bad the structural damage was, which sets the damage multiplier. |
| mi | Mileage | The miles on the odometer at the time of the accident. |
| rule | Mileage multiplier | Whether the mileage multiplier drops in 20,000-mile steps or on a straight line to 0 at 100,000 miles. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| dv | Diminished value | Base loss × damage multiplier × mileage multiplier. |
| base | Base loss (10% cap) | 10% of the value before the accident. |
| damageMultiplier | Damage multiplier | From the damage you chose. |
| mileageMultiplier | Mileage multiplier | From the mileage and the rule you chose. |
| after | Value after repair | The value before the accident minus the diminished value. |

## Method

Diminished value = value before the accident × 10% × damage multiplier × mileage multiplier. Mileage multiplier in steps: 1 − 0.2 × (whole 20,000-mile steps), 0 from 100,000 miles; on a straight line: 1 − miles ÷ 100,000, 0 from 100,000 miles.

## Assumptions

- The 17c formula is an insurer’s method from a Georgia class-action settlement; it is not a law, and a market appraisal often finds a larger loss.
- The value before the accident is the market value, which you look up and type.
- Whether you can claim diminished value, and from whom, depends on your state and policy.

## Worked examples

1. val = $30,000.00, dmg = 0.5, mi = 45,000, rule = steps gives base = $3,000.00, mileageMultiplier = 0.6, dv = $900.00, after = $29,100.00. Source: SnapClaim, Demystifying the Diminished Value 17c Calculator. https://snapclaim.com/diminished-value-17-c-calculator/ ($30,000 value, 10% = $3,000, moderate damage 0.50, 45,000 miles 0.60: $900).
2. val = $21,100.00, dmg = 0.5, mi = 43,000, rule = linear gives base = $2,110.00, mileageMultiplier = 0.57, dv = $601.35. Source: 17cformula.com, The 17c Formula (base loss 10% of value; damage modifiers 1.00 to 0.00; mileage modifiers 1.0 at 0 miles to 0.0 at 100,000+). https://17cformula.com/17c_diminished_value_formula_ebook.html (2010 MX-5 at 43,000 miles, $21,100: base $2,110, × 0.57, × 0.5 = $601, rounded).
3. val = $150,000.00, dmg = 0.75, mi = 25,000, rule = steps gives base = $15,000.00, mileageMultiplier = 0.8, dv = $9,000.00. Source: SuperCar Claims, 17c Formula. https://www.supercarclaims.com/17c-formula/ ($150,000, base $15,000, damage 0.75, mileage 0.80: $9,000).
4. val = $40,000.00, dmg = 1, mi = 120,000, rule = steps gives mileageMultiplier = 0, dv = $0.00, after = $40,000.00. Source: 17cformula.com, The 17c Formula (base loss 10% of value; damage modifiers 1.00 to 0.00; mileage modifiers 1.0 at 0 miles to 0.0 at 100,000+). https://17cformula.com/17c_diminished_value_formula_ebook.html (100,000+ miles: modifier 0.0).

## FAQ

### What is diminished value?

It is the market value a car loses because it has been in an accident, even after a good repair. Buyers pay less for a car with an accident history, so the repaired car is worth less than the same car with no accident.

### What is the 17c formula?

A formula from the 2001 Georgia class action State Farm v. Mabry, named after paragraph 17c of the settlement. It takes 10% of the car’s value before the accident as the most it can lose, then multiplies by a damage multiplier (1.00 to 0.00) and a mileage multiplier (1.0 to 0.0).

### How do I calculate diminished value?

Multiply the value before the accident by 10%, then by the damage and mileage multipliers. A $30,000 car with moderate damage (0.50) and 45,000 miles (0.60) gives 3,000 × 0.50 × 0.60 = $900.

### Which mileage multiplier is right?

Many 17c worksheets drop the multiplier by 0.2 at each 20,000 miles: 1.0 under 20,000, 0.8 under 40,000, 0.6 under 60,000, 0.4 under 80,000, 0.2 under 100,000 and 0 from there. Some interpolate on a straight line instead, so 43,000 miles gives 0.57. Choose the rule your insurer uses.

### Is the 17c result what I will get?

Not always. The formula is an insurer method, not a law, and it caps the loss at 10% of the value. Critics point out that a market-based appraisal often finds a loss several times larger. You can dispute a low offer with an independent appraisal.

### Can I claim diminished value?

It depends on your state and on who caused the accident. Claims against the at-fault driver’s insurer are the most common; a claim on your own policy is often excluded. Ask your insurer or your state insurance department.

## Sources

- 17cformula.com, The 17c Formula: What It Is, Why It’s Wrong & What Georgia Drivers Can Do (origin in State Farm v. Mabry; mileage modifiers 1.0 to 0.0 by 20,000 miles; damage modifiers 1.00 to 0.00; MX-5 example at 43,000 miles). https://17cformula.com/17c_diminished_value_formula_ebook.html (retrieved 2026-10-05)
- SnapClaim, Demystifying the Diminished Value 17c Calculator ($30,000 value, 0.50 damage, 0.60 at 45,000 miles: $900). https://snapclaim.com/diminished-value-17-c-calculator/ (retrieved 2026-10-05)
- SuperCar Claims, 17c Formula (pre-loss value × 10% × damage multiplier × mileage multiplier; $150,000 example: $9,000). https://www.supercarclaims.com/17c-formula/ (retrieved 2026-10-05)
- SecondAppraisal, Diminished value calculator (17c formula) (damage modifiers 1.00 severe, 0.75 major, 0.50 moderate, 0.25 minor, 0.00 none). https://secondappraisal.com/tools/diminished-value-calculator (retrieved 2026-10-05)