Diminished Value Calculator: 17c Formula, Example & Limits

This diminished value calculator shows a 17c-style estimate, not your car’s actual loss of resale value. It multiplies the pre-accident value by a 10% base, a damage factor, and a mileage factor. Use it to understand a calculation you have been given, then check the evidence behind the claim.

With the example inputs below—$25,000, moderate damage, and 40,000–59,999 miles—the result is $750. That is the arithmetic for those inputs. It is not a promise of a $750 offer or proof that a higher amount is owed.

Calculate the 17c estimate

Enter the vehicle’s value immediately before the accident, then choose the categories. If you are checking an insurer’s worksheet, use its stated inputs first so you can identify where your numbers differ.

How the calculator works

The damage factors available here are 1.00, 0.75, 0.50, 0.25, and 0. The mileage factors run from 1.00 for under 20,000 miles to 0 for 100,000 miles or more. These are the categories used in this tool. They do not independently measure the quality of a repair or buyers’ willingness to pay.

Does a zero result mean the car lost no value?

No. Selecting a zero damage or mileage factor makes the product zero. That result follows from the formula; it does not inspect the vehicle, check its history, or compare market transactions. Conversely, a positive result does not establish that a claim is covered.

Is 17c an official value for every claim?

No single formula should be treated as an individual appraisal. Georgia’s insurance commissioner stated in Directive 08-P&C-2 that the department had not endorsed a specific diminished-value formula as the definitive amount and that evaluation should consider relevant information. Read the original 2008 directive (PDF copy).

That does not mean every insurer must hire an independent appraiser. The Georgia Court of Appeals explained that distinction in Amica Mutual Insurance Co. v. Sanders (2015). The case is Georgia-specific; it is not a nationwide eligibility rule. Read the court’s decision.

What should you compare with the insurer’s number?

Compare the underlying evidence, not an invented percentage. There is no reliable basis for this tool to tell you that an appraiser will always find a loss of 10–25% of your car’s value.

• Vehicle details: year, model, trim, options, mileage, and pre-accident condition.
• Damage and repair records: the original estimate, final invoice, photographs, and explanations of major repair work.
• The valuation: the insurer’s inputs, calculation, and reasons for the offer.
• Market evidence: relevant comparable vehicles or an appraisal that explains its method and supporting data.

An appraisal is evidence you can evaluate and submit. It does not guarantee agreement, recovery, or reimbursement of its cost. Before paying, ask what the report covers, which records it needs, and whether the provider offers any support if the valuation is questioned.

Your next step after using the calculator

1. Ask for the written calculation. Keep a copy of the offer and identify which input or assumption you dispute.
2. Check the applicable claim route. Your state, policy, responsibility for the accident, and whether you claim against your own insurer or another driver can change the answer.
3. Organize supporting records. Separate repair costs, loss of resale value, and any injury claim.
4. Choose a proportionate next step. That may be asking for a correction, obtaining further valuation evidence, or getting advice about a disputed claim. Compare any service fee with what it actually provides.

Get the free diminished-value document checklist. You can download it without providing contact details or uploading claim records.

Related guides

• Diminished-value appraisals
• Organizing a diminished-value demand letter
• Responding to a diminished-value offer
• State Farm claims
• Progressive and GEICO claims
• Virginia, North Carolina, and Colorado