How to Use the Diminished Value Calculator

How to Use the Diminished Value Calculator

The JusticeFinder diminished-value calculator compares two sets of sample assumptions. It does not look up a car's market value, inspect damage, determine coverage or predict an insurer's payment. Use it to understand how the displayed factors change the arithmetic, then keep any actual vehicle valuation and claim analysis separate.

Open the diminished-value calculator and follow the example below. The same calculations are available in English and Spanish. Reset returns the form to the sample vehicle; it does not restore personal records.

What the tool is for

The tool is useful when you want to unpack a formula, compare inputs or see why a mileage cutoff changes a result. It is not designed to answer “What will my insurer pay?” or “What is my car worth today?” A positive result is not proof of an entitlement, and a zero result is not proof that no value was lost.

There are two outputs: a 17c-style calculation and an illustrative percentage band. These labels describe the model implemented here. The guide does not claim that its factors are required by law or that every insurer uses them.

For the wider vehicle-claim process, use the property-damage guide. If the issue is whether a vehicle is being treated as a total loss, use the total-loss guide instead of interpreting this calculator as a repairability test.

Gather the inputs and record their source

Write down where the vehicle value came from: an insurer's report, an appraisal or your own provisional assumption. A comparison using an unverified input remains provisional even if the calculator displays cents.

The mileage slider moves in 5,000-mile steps. It is a simplified input, not an odometer record. Keep exact mileage in your claim documents, particularly if it sits near a factor boundary. Do not round a real figure in an appraisal merely because this demonstration uses a stepped slider.

Understand the two calculations

The 17c-style output is:

Entered vehicle value × 10% × severity factor × mileage factor

The other output is a band:

Entered vehicle value × sample low/high percentages × the same mileage factor

The percentages are fixed examples in the tool. They were not calculated from comparable sales, a vehicle inspection or an appraisal database. Choosing a category changes both branches; it does not add new evidence about your car.

The headline starts at the lower of the 17c-style output and the sample band's low end. It ends at the higher of the 17c-style output and the band's high end. That span describes the calculations, not a confidence interval, likely settlement range or legal floor.

Worked example: $28,000 and moderate damage

At 45,000 miles, the mileage factor is 0.6. With moderate selected:

• 17c-style result: $28,000 × 10% × 0.5 × 0.6 = $840.
• Sample low: $28,000 × 4% × 0.6 = $672.
• Sample high: $28,000 × 10% × 0.6 = $1,680.
• Headline comparison: $672–$1,680, because $840 is already inside the band.

If you select major while keeping the same value and mileage, the 17c-style result becomes $1,260 and the sample band becomes $1,344–$2,688. The headline is then $1,260–$2,688. The different lower endpoint follows from the comparison rule; it is not a finding that a claim has a minimum value.

These are invented numerical inputs for explaining the software, not a real vehicle valuation or a case study. You can reproduce them in the tool, change one input at a time and see which part of the calculation changes.

Why high mileage produces zero

Both calculations use this same table:

At 100,000 miles and above, multiplication by zero makes both results zero. The page displays an explanation of that limitation. It does not conclude that a repaired high-mileage vehicle cannot have a remaining loss in value.

The table also causes abrupt changes at its boundaries. For the same $28,000 moderate example, 95,000 miles produces $280 and a $224–$560 sample band; 100,000 miles produces zero. That jump is built into the model. It is not evidence that a market price suddenly changes by that amount.

What the insurer selection changes

Selecting your own insurer changes the accompanying questions about policy provisions and state rules. Selecting the other driver's insurer changes the questions about responsibility and evidence. Neither selection changes the arithmetic or makes a claim available.

The Texas TDI bulletin of April 6, 2000 distinguishes collision/comprehensive, third-party liability and uninsured/underinsured-motorist claims. This historical example illustrates why the coverage matters; it is not a current nationwide eligibility chart. Check the applicable policy and current authority for the actual claim.

Keep the calculation and evidence separate

If you obtain an appraisal or valuation opinion, read the reasoning behind it. Useful questions include which vehicle details were used, what repairs were completed, what history was considered, which comparisons were selected and how differences were adjusted. Record what the author inspected and what was assumed.

A repair invoice documents work and charges. It does not by itself calculate a post-repair market difference. Likewise, an asking price is not automatically a completed sale, and a trade-in offer may answer a different valuation question. Identify what each document actually measures rather than presenting unlike numbers as a single comparison.

Keep the repair-cost tracker with your records, but label calculator output separately as an illustrative calculation. If you send the output to someone else, include the selected inputs and the model limitations. Do not describe the fixed percentage band as market research.

Common mistakes to avoid

• Treating the 17c-style result as a minimum payment or claim cap.
• Calling the sample percentages observed buyer discounts.
• Interpreting the high-mileage zero as proof of no loss.
• Selecting a more severe category solely to increase the result.
• Assuming the insurer selector checks coverage or state eligibility.
• Combining repair cost and every other number without checking what each represents.
• Treating displayed cents as a sign that the underlying assumptions are precise.

At zero vehicle value, the calculator asks for a positive input. Start with a value whose origin you can explain, inspect the two branches, and use reset if you want to return to the example. The useful outcome is understanding the assumptions, not finding a number that promises a payment.

Method and source review

Reviewed September 11, 2026. The formulas, factors, limits and examples were checked against JusticeFinder's calculator implementation. They document this software, not an independent appraisal method. No claim is made that the sample bands have been validated against market transactions.

The historical Texas bulletin does not supply or validate the tool's percentages. For an actual claim, check current policy terms, state requirements and evidence before relying on a valuation or signing a release.