Vehicle Diminished Value Calculation
Diminished value is the difference between your vehicle's pre-accident and post-repair resale value. This page explains how it is calculated, how to challenge an adjuster's report within three business days, and when it cannot be claimed.
Diminished value is the difference between your vehicle's resale value before the accident and after repair. You can calculate it. If an insurer or adjuster has given you an amount, compare the two. You have only three business days to challenge the report.
The calculator itself is available on the Turkish page: Araç Değer Kaybı Hesaplama. Linked pages are in Turkish. Its results are based on the used-car values you enter and are not an adjuster's or a court expert's calculation. If you do not know the market values, the calculator does not produce an amount. Instead, it shows the criteria used to determine compensation.
What Is Vehicle Diminished Value?
A vehicle damaged in a traffic accident is treated as an "accident-damaged vehicle" on the used-car market, even if it has been repaired to the highest standard, and it sells for less. This loss in value is a real loss. Under the tort provisions of the Turkish Code of Obligations (TBK), it must be compensated, and it is claimed from the other party's compulsory motor third-party liability insurance (compulsory traffic insurance).
Original replacement parts do not by themselves eliminate diminished value. The fact that parts were replaced and the vehicle was repaired still affects its resale value.
How Is Diminished Value Calculated?
Established practice uses a single measure: the difference between the vehicle's undamaged used-car market value on the date of the accident and its used-car market value after repair. The portion corresponding to the claimant's own fault is then deducted from that amount.
The method in brief
Diminished value = undamaged resale value − post-repair resale value
Amount payable = diminished value × the other party's share of fault
1 July 2026: the two methods now align
The diminished value clause of the General Conditions of compulsory traffic insurance was amended in the Official Gazette of 12 June 2026 and took effect on 1 July 2026. The new text provides that diminished value is determined by taking into account the vehicle's make, age, model, level of wear, damaged parts and prior damage history, together with the difference between its pre-accident and post-repair used-car sale values. The former text's reference to a coefficient table has been removed. Amendments to the General Conditions apply to policies issued after their effective date, so the date of your policy determines which text applies.
Both values are determined by reviewing comprehensive insurance (kasko) value lists and market listings, and by looking at the vehicle's physical condition. For this reason, diminished value cannot be found with a fixed percentage or a table. The calculator on the Turkish page likewise produces no amount unless you enter these values.
The 2026 Procedure: Adjuster Assignment and a Single Report
The Regulation on the Assignment of Insurance Loss Adjusters (Official Gazette of 12 February 2026, in force since 1 April 2026) introduced rotation-based assignment of adjusters through a central system for traffic insurance claims. When assessing the damage, the assigned adjuster must also calculate diminished value in the same report, applying the principle of actual loss.
In practice, if an adjuster has been assigned to your file, you do not need to file a separate claim for diminished value. If no adjuster has been assigned, one will be assigned when you claim diminished value.
Coverage is expanding in stages
Rotation-based adjuster assignment was first piloted in Bursa and Ordu. A Board decision dated 30 June 2026 extended the pilot period to 1 August 2026 and added Balıkesir, Erzurum, Kayseri, Kütahya, Manisa, Uşak and Van. No regulation has announced that the system now applies nationwide. You should therefore check which procedure applies to your file and whether an adjuster has been assigned.
Challenging the Report: Three Business Days
You can challenge the adjuster's findings within three business days of the notification that the report has been entered into the system. This deadline is very short, and an objection is the fastest remedy you have against the diminished value amount.
- Objection. File an objection within three business days of the notification. A second adjuster is then assigned through the system.
- Second adjuster's report. If you make a request within three business days of notification of the second report, an umpire adjuster is assigned.
- Umpire adjuster. The umpire is chosen from among people who have actively worked as adjusters in the relevant line for at least ten years. The umpire's report is accepted as final.
Going through this route at the appraisal stage does not by itself close off the Insurance Arbitration Commission or the courts. But missing the deadline can leave you with a longer and more expensive path.
When Diminished Value Cannot Be Claimed
- Scrapped or deregistered vehicles: diminished value claims for vehicles taken off the road (deregistered) or scrapped because of the damage fall outside compulsory traffic insurance coverage.
- Your own share of fault: the portion corresponding to the claimant's own fault is not covered. Compensation is paid only in proportion to the other party's fault.
- Indirect losses: loss of use, replacement-vehicle costs, loss of earnings and business interruption cannot be claimed from compulsory insurance. These are assessed separately against the party at fault.
- Non-pecuniary damages: these fall outside compulsory traffic insurance coverage.
- Voluntary motor liability (İMSS) policy: this cover applies only after the compulsory insurance limits have been used up. If the policy does not include diminished value cover, this item is not paid.
Insurance Arbitration and Litigation
Before going to arbitration or court, you must make a written application to the insurance company. This is a precondition to filing suit. If the insurer does not respond within fifteen days, or its response does not satisfy your claim, you may apply to the Insurance Arbitration Commission or file a lawsuit.
An application filed while the appraisal is pending may be turned away
Under the Authority's circular dated 5 August 2026, if the insurance company documents that it assigned an adjuster in time and that the report could not be completed for reasons not attributable to it, the claim is not treated as denied, and the response is not treated as failing to meet the claim. At this stage, the right step is not to rush to arbitration but to challenge the report within the deadline.
In arbitration, awards in disputes below TRY 35,000 have been final since 22 January 2026. For amounts of TRY 35,000 or more, an objection can be filed with the Commission. In litigation, the competent court depends on whom you sue. Claims against the insurance company go to the Commercial Court of First Instance (Asliye Ticaret Mahkemesi). Claims against the driver at fault or the vehicle operator go to the Civil Court of First Instance (Asliye Hukuk Mahkemesi).
The limitation period is two years from the date on which you learn of the damage and of the person liable to pay compensation, and in any case ten years from the date of the accident. If the accident constitutes a crime, the longer period under criminal law applies.
Frequently Asked Questions
What is vehicle diminished value?
A vehicle damaged in a traffic accident has an accident record, so it sells for less on the used-car market even if it has been repaired to the highest standard. This loss in value is a real loss and is claimed from the other party's compulsory traffic insurance.
How is diminished value calculated?
The basis is the difference between the vehicle's undamaged used-car market value on the date of the accident and its used-car market value after repair. The portion corresponding to the claimant's own fault is deducted from that amount. Both values are determined through market research and a physical inspection of the vehicle, so the amount cannot be found with a table or a fixed percentage.
What changed as of 1 July 2026?
The diminished value clause of the General Conditions of compulsory traffic insurance was amended in the Official Gazette of 12 June 2026 and took effect on 1 July 2026. The new text provides that diminished value is determined by taking into account the vehicle's make, age, model, level of wear, damaged parts and prior damage history, together with the difference between its pre-accident and post-repair used-car sale values. The former text's reference to a coefficient table has been removed.
Do I need to file a separate claim for diminished value?
If an adjuster has been assigned to your file, diminished value is calculated in the same report, and no separate claim is needed. If no adjuster has been assigned and you claim diminished value, an adjuster will then be assigned. The system is being extended in stages, in terms of both the provinces covered and the procedure used, so you need to check the status of your own file.
Can I challenge the diminished value amount in the adjuster's report?
Yes. You can challenge the adjuster's findings within three business days of the notification that the report has been entered into the system. A second adjuster is then assigned. If you make a request within three business days of notification of the second report, an umpire adjuster with at least ten years of experience in the relevant line is assigned, and the umpire's report is accepted as final.
What happens if I miss the objection deadline?
The deadline runs from the moment the notification reached you, and that moment may be disputed in a given case. Even if the objection route at the appraisal stage has closed, the Insurance Arbitration Commission and the courts are considered separately. It is therefore worth having your file reviewed even if the deadline appears to have passed.
What can I do if the insurance company pays too little?
You must first make a written application to the insurance company. This application is a precondition to filing suit. If the insurer does not respond within fifteen days, or its response does not satisfy your claim, you may apply to the Insurance Arbitration Commission or file a lawsuit.
Can I apply to arbitration before the adjuster's report is completed?
Under the Authority's circular dated 5 August 2026, if the insurance company documents that it assigned an adjuster in time and that the report could not be completed for reasons not attributable to it, the claim is not treated as denied. An arbitration application filed in that situation may be turned away at the preliminary review. The right step is not to rush the application but to challenge the report within the deadline.
Can I claim diminished value if my vehicle was scrapped?
Under the Highway Traffic Law (KTK), diminished value claims for vehicles taken off the road (deregistered) or scrapped because of the damage fall outside compulsory traffic insurance coverage. Whether the loss can be claimed from the party at fault under the general provisions must be assessed separately.
Does my own fault reduce the compensation?
Yes. The portion corresponding to the claimant's own fault falls outside compulsory traffic insurance coverage. Compensation is calculated only on the other party's share of fault. If the accident was entirely your fault, you cannot claim diminished value.
Can I recover the cost of a replacement vehicle while mine is being repaired?
Indirect losses such as loss of use, loss of earnings and business interruption fall outside compulsory traffic insurance coverage. These claims are assessed separately against the party at fault under the general provisions.
Which court hears a diminished value lawsuit?
The competent court depends on whom you sue. Lawsuits against an insurance company are absolute commercial cases, so the Commercial Court of First Instance has jurisdiction. A tort claim against the driver at fault, the vehicle operator or the vehicle owner goes to the Civil Court of First Instance.
What is the limitation period for a diminished value claim?
The period is two years from the date on which you learn of the damage and of the person liable to pay compensation, and in any case ten years from the date of the accident. If the accident also constitutes a crime, the longer limitation period under criminal law applies. The calculation therefore depends on the specific case.
Review Your Adjuster's Report
You can review your adjuster's report with Mesut İlme, attorney at law. Whether the amount you were given is appropriate, which objection deadline applies and what course to take all depend on your file. Book an online or in-person appointment: Book an appointment online or call +90 226 911 07 99. Consultation fees start at TRY 4,800 (VAT included).
Consultations are held in Yalova or by video call, in Turkish or English. Write to us with a short description of the matter and we will propose a time.
Phone: 0 (226) 911 07 99 · Office hours Mon–Fri, 09:00–18:00 (Türkiye time).
This page is an English edition of the Turkish original, prepared and reviewed at Ilme Law Office; where the two differ, the Turkish text prevails. It is general information under the advertising rules of the Union of Turkish Bar Associations and does not replace advice on your specific case. Read the Turkish original.