How Government Appraisal Rates work.

General Note: to compile this page we used claude on some occasions for thai translations and research.

We did a bit of digging, there is not much data available, yes there is but in PDF files in thai Language.

First of all there is the website: https://assessprice.treasury.go.th/ a lot of info there but not easy to access.

Note 1. The government makes a difference for Residential, private usage and Company use. This is based on the property’s actual physical use category (ประเภทการใช้ประโยชน์จริง) as classified by the tessaban. A house in company name, being marketed for sale, but still standing as an ordinary residential structure (not rented out commercially, not run as a business), typically gets classified as residential (ที่อยู่อาศัย) — even though the owner is a company — and residential carries a much lower rate table.

Private use:

Company use:

Step 1 Calculate the appraisal price land value, zoom in to the actual location via https://landsmaps.dol.go.th/ Both in English and Thai, or use the treasury website if you have on hand the titledeed.

Step 2 Appraisal price for building is gathered into categories, Here the data for chonburi (2026) Every 4 years the appraisal price (and depreciation) is recalculated. the current period is (2566–2569) 2023-2026

Thai Government Building Code Definitions: Treasury Department (กรมธนารักษ์) — Standard Construction Definitions

Translated from the Treasury Department (กรมธนารักษ์) standard construction definitions document (“คำนิยามประกอบแบบมาตรฐานสิ่งปลูกสร้าง”), used to classify structures for government property appraisal purposes.

Depreciation

Depreciation is also part of how the Treasury Department (กรมธนารักษ์) calculates the assessed value of a building/house, separate from the land value. Here’s how it generally works:

The formula
Assessed building value = (Base unit price per sq.m. for that construction code, e.g. 105, 107, etc.) × (floor area) − accumulated depreciation, based on the building’s age.

Depreciation mechanics

• Each construction type/code has its own annual depreciation rate schedule (a permanent reinforced-concrete house depreciates more slowly per year than, say, a wooden or semi-permanent structure).
• Depreciation is applied per year of age from the year construction was completed (or the year it was last officially re-appraised, if renovated/rebuilt).
• There’s a floor on residual value — even a very old house won’t depreciate to zero. The Treasury Department’s tables set a minimum remaining value (commonly cited around 10% of the original base assessed value) so old structures still carry some appraised value, however old.
• The Treasury updates its base unit prices per construction code periodically (this is separate from the depreciation schedule itself, which is a standard table applied uniformly).

When you get pay taxes or sell a home an official appraisal from the Land Office or Treasury Department already has depreciation baked in based on the building’s age on record — you don’t need to calculate it yourself. If you want the actual depreciation rate table for a specific code (percentage per year), you have to search the current Ministerial Regulation (กฎกระทรวงการกำหนดหลักเกณฑ์การคำนวณราคาประเมินสิ่งปลูกสร้าง) rather than approximate it but there is no info known data online available .

The following, data we could find:

Here’s what the governing regulation (กฎกระทรวง การกำหนดราคาประเมินที่ดินหรือสิ่งปลูกสร้างฯ พ.ศ. 2563, issued under the Asset Appraisal for State Benefit Act B.E. 2562) says:

Legal definition of building depreciation (ค่าเสื่อมราคาสิ่งปลูกสร้าง):
The regulation defines it explicitly as depreciation resulting from the age of the structure since construction, deducted as a percentage per year, according to the type of structure.

• The Provincial Committee (คณะกรรมการประจำจังหวัด) calculates the base building value from the standard construction-cost tables (the same code system in your PDF — 101, 105, 107, etc.), based on materials and labor cost data.
• Every appraisal report for a building must include, among other things, a depreciation rate table (ตารางกำหนดอัตราค่าเสื่อมราคาสิ่งปลูกสร้าง) as a mandatory component — separate from the base cost table and the final summary.
• Final appraised building value = base construction-cost value − accumulated depreciation, applied per year of the building’s age, at the rate set for that specific construction code.

What’s not in this regulation:
The actual numeric depreciation percentage-per-year table (e.g., “X% per year for code 105, Y% per year for code 402”) isn’t published in the ministerial regulation itself — it’s set separately by the central Valuation Committee (คณะกรรมการกำหนดราคาประเมินทุนทรัพย์) and issued as an internal annex/circular per accounting round (currently the 2566–2569 round). These annex tables aren’t reliably indexed on the open web — they’re typically obtained directly from the Land Office or Treasury Department provincial office when they run an appraisal, or via the Treasury’s own lookup portal.