Behind every property transaction in Thailand sits a number that few foreign buyers truly understand: cadastral value. It is the official price set by the state. It shapes what you pay and what you declare, and it underpins the guarantees of any well-built structure. Once you understand it, you stop accepting a figure handed to you and start reading how an investment actually works.
This eighteen-part THEVA series takes the facts one at a time, with the legal texts at hand. Earlier articles covered the legal tools and the guarantees of the model. This final piece lays down the factual foundation that two of those guarantees rely on: rent indexation at lease renewal and the basis of the buy-back. It is a technical notion, but it changes everything once you master it.
Article 18 of 18 explains what cadastral value is, who sets it and how it evolves, and why it serves as the neutral anchor of a well-structured investment.
Source: official cadastral value system, Thai Treasury Department.
What Cadastral Value Actually Is
Cadastral value is the official appraisal price of a property, set by the state. The Treasury Department's land appraisal price is the reference used to calculate fees when land is bought, sold or transferred. It is also used to calculate land and building taxes, which depend on the assessed value. In short, it is the benchmark figure of the Thai property system.
Keep it separate from market price. Cadastral value is not what a property actually sells for between a buyer and a seller. It is an administrative value, set by the state to serve as a basis for calculation.
The appraisal is carried out by the Treasury Department together with the Land Office. Because revisions are infrequent, the official figure can lag behind market value. It serves as the minimum for setting land and transfer taxes, specific business tax and stamp duty. There are three categories of appraisal: land, condominiums and buildings.
Who Sets It: The Four-Year Cycle
Cadastral value is not frozen. The Treasury Department reviews it every four years, working with the Land Office, and each cycle sets the applicable schedule until the next revision.
The calendar is known in advance. The current cycle runs from 2023 to 2026, and the new 2027-2030 schedule officially takes effect on 1 January 2027. That regularity makes the trajectory predictable. You do not depend on a figure negotiated case by case, but on a published state schedule that applies to everyone over a defined period.
The last revision sets the tone. When the current schedule came into force, the national land appraisal price rose by 8.93%, and the building appraisal price by 6.21%. Land values are revised to reflect real changes in the market and in infrastructure. This explains why land in particular sees its official value climb from one cycle to the next.
A Reference Nobody Can Bend
This is where cadastral value earns its place in an investor's thinking. It combines qualities that no private estimate offers at the same time.
Official, Public and Verifiable
It is official, set by the state rather than by a party to the transaction. Nobody can inflate or understate it to serve their own interests in a contract.
It is also public, and you can check it yourself. The Treasury Department runs an official portal, available in Thai and English, where anyone can verify a property's appraisal price free of charge. You search by title deed number and province, or by building type, at assessprice.treasury.go.th. You need neither a hired expert nor a seller's word to confirm the figure.
Finally, it is stable. Revised every four years on a known calendar, it does not move with market moods or a seller's preferences. For a long-term guarantee, this is exactly the kind of reference you need: known in advance and binding on everyone.
Below Market, With a Narrowing Gap
One point comes up often, so it deserves a clear answer. At any given moment, cadastral value is generally lower than market price. This is a feature of the system rather than an anomaly, and it follows from revisions taking place only every four years.
That gap is shrinking, and the trend is structural. The Treasury Department has worked with major financial institutions to feed real transaction prices and loan appraisal data into its Big Data system. The goal is to close the gap between the official appraisal and the actual market price, which has historically been in the range of 20 to 40%. The state is steadily bringing its reference closer to market reality, which makes it an even more reliable basis for calculation.
"Cadastral value is the state's official price, public and verifiable by anyone, revised every four years on a known calendar. Nobody can manipulate it, and that is precisely what makes it a solid anchor for an investment."
Why It Matters for Your Investment
This is not only a tax matter. Cadastral value sits at the heart of two guarantees in a well-built structure, which is why this series gives it a full article.
Indexing Rent at Lease Renewal
A good contract does not leave renewal rent to an uncertain negotiation. Instead, it indexes the rent to the official cadastral value. The rent then follows an objective state schedule and rises at a controlled, predictable pace rather than at the lessor's discretion. We explain how this works in our article on lease renewal priority.
Anchoring the Buy-Back
When a villa buy-back is guaranteed, it rests on cadastral value precisely because that value is neutral and indisputable. Neither party can challenge a figure set by the state and open to public consultation. You rely on an official reference, not on a buyer's good faith or an appraiser's opinion. Our article on the cadastral value buy-back covers this guarantee in detail.
The principle is the same in both cases. A subjective judgement, which is a frequent source of disputes, is replaced by an official figure that nobody can twist. That neutrality protects you far more than any amount promised in a brochure.
What It Changes for Foreign Buyers
When you invest abroad, your first fear is being misled by figures you do not control. Cadastral value answers that fear directly. It is an official price that anyone can verify, revised on a known calendar. Both the taxes you pay and the guarantees that protect your property rest on it.
A market built on such a reference is easier to read and safer to enter. Thailand anchors its system in a transparent state schedule that you can consult yourself on the Treasury Department's official portal. For a serious investor, that means predictability. It is also why a sound model builds its guarantees on this schedule rather than on discretionary promises.
A serious investor does not try to guess a number. They look for a reference that holds. Cadastral value is one, and it is the quiet foundation of a well-structured investment.
Final Thoughts
Cadastral value is far more than a technical footnote for accountants. It is the state-set figure behind both the taxes you pay and the guarantees that protect your investment, and no seller, lessor or developer can manipulate it. That neutrality is why this series ends here, on the reference that THEVA's model uses for its guarantees, and the one any investor in Thailand can look up for themselves.
