Free tool · 17c method

Diminished value calculator

Your car is worth less after an accident, even repaired perfectly. This is the 17c formula insurers use — with every line of the math printed, so you can check it.

Reviewed August 24, 2026 · methodology · changelog
Free · No sign-up · 17c formula

Your diminished value estimate

Estimated diminished value$0 – $0

The low end is the insurer-standard 17c result; the high end reflects what independent appraisals commonly find. Educational estimate, not an appraisal or legal advice.

How the math works

The 17c formula, step by step

Insurers rarely volunteer diminished value — you usually have to claim it. When they do calculate it, most use the 17c method, and every input is visible in the calculator above:

  • Base loss of value: your car's pre-accident market value, capped at 10%. This cap is the insurer's assumption of the maximum any accident can take off the price.
  • Damage modifier: 1.00 for severe structural damage down to 0.00 for cosmetic-only damage. Structural damage on the history report scares buyers most.
  • Mileage modifier: 1.00 for a nearly-new car down to 0.00 past 100,000 miles — the logic being that high-mileage cars have already lost most of their value.

Why we show a range

The 17c result is the floor, not the truth. Independent appraisers regularly find diminished value 30–60% higher because the 10% cap and the mileage haircut have no basis in how used-car buyers actually price accident history. If the 17c number for your car is meaningful money, an independent appraisal (typically $300–$500) often pays for itself many times over.

SourcesState insurance regulations on first- vs third-party DV claims · The 17c method as applied in standard insurer claim practice
Common questions

FAQ

What is diminished value?

Diminished value is the gap between what your car was worth before the accident and what it's worth after being repaired. Even a perfect repair leaves an accident on the vehicle history report, and buyers pay less for a car with an accident history.

What is the 17c formula?

17c is the calculation most insurers use, named after the paragraph in a Georgia claims settlement where it first appeared: pre-accident market value × 10% cap × a damage modifier (0 to 1) × a mileage modifier (0 to 1). It's insurer-friendly — the 10% cap and stacked modifiers push the number down — which is why our result shows the 17c figure as the low end of a range.

Can I claim diminished value from my own insurer?

It depends on your state. Most states let you claim diminished value from the at-fault driver's insurer (a third-party claim). Only a minority — Georgia is the clearest example — require your own insurer to pay diminished value on a first-party claim. Check your state's rule before filing.

Is this an official appraisal?

No. This is an educational estimate using the industry-standard formula. If your claim is worth pursuing, a licensed independent appraiser's report is what carries weight in negotiation.