Condominium Price Per Usable Area and Price Adjustment on Final Measurement

Why the Price of a Unit Depends on How the Area Is Measured

In Thailand, the price of a condominium unit is almost always tied to area: the contract states a price per square metre, and the total amount is that rate multiplied by the stated area. For this reason, the critical question becomes exactly which area the developer uses in the calculation. The measurement methodology directly determines how much you pay and for what.

The main pitfall is that the 'saleable area' and the actual space you use inside the walls are not the same thing. The difference can amount to several square metres and, in monetary terms, to a significant sum.

What Is Included in the Saleable Area

Under the Condominium Act (Chapter II), the boundaries of private ownership of a unit are defined in a specific way, and measurement for sale purposes is normally carried out to the centre line of walls that do not form part of the common property. This means the following:

• External (facade) walls of the building are common property of the condominium. They are jointly owned by all unit owners through the condominium juristic person.
• Walls between neighbouring units are private property, divided between the owners of the adjoining units.
• As a result, the saleable area often includes half the thickness of a shared wall, and sometimes part of a space you do not actually use.
• Permanently fixed equipment on the facade (for example, the outdoor compressor unit of an air conditioner mounted on an external wall) forms part of the common property, not your unit.

It follows that the 'usable area' (the space you can actually measure with a tape measure across the floor inside the unit) is generally smaller than the figure you are paying for.

Types of Area: What to Look for in the Contract

The key rule: always clarify which measurement methodology is used for the area stated in the contract and whether it matches the area that will ultimately be recorded in the title document (the unit title issued by the Land Department after registration of the condominium).

How Price Adjustment Works

Because the exact area is unknown before construction is complete, contracts for off-plan purchases almost always include a price adjustment clause based on the outcome of the final measurement. The logic is as follows:

• The contract fixes a price per square metre and a preliminary area.
• Once the building is complete, an official measurement is carried out for the purpose of issuing the unit title.
• If the actual area is greater than stated, the buyer pays the difference at the same rate.
• If it is smaller, the developer refunds the overpayment or reduces the outstanding balance.

It is important to check whether the contract contains a tolerance threshold, within which a discrepancy triggers no adjustment. This is typically 1-5%. A buyer-friendly formulation provides for adjustment in both directions, and if the deviation exceeds a specified percentage (for example, more than 5%), the buyer has the right to withdraw from the transaction and recover all amounts paid. If the clause is one-sided (requiring additional payment but providing no refund) that is a signal to negotiate.

From the perspective of general sale and purchase law (the Civil and Commercial Code, CCC sections 453 and following), the seller is obliged to deliver the thing in accordance with the contract; a sale 'by measure and weight' implies price adjustment where the quantity differs. The adjustment clause is therefore not a developer's whim but a standard mechanism protecting both parties when drafted fairly.

Connection to the 49% Foreign Ownership Quota and Remittance from Abroad

Price and area directly affect a foreign buyer's transaction at two additional points:

• The 49% quota. Foreigners may collectively own no more than 49% of the total saleable area of all units in a condominium (Condominium Act). Management must confirm that, at the time of registration, space remains available within the foreign ownership quota for your specific area.
• Remittance of funds from abroad. Money for the purchase must arrive in Thailand in foreign currency and be converted into Thai Baht, after which the bank issues a Foreign Exchange Transaction form (FET, formerly known as Tor Tor 3). This document is required for registration of foreign ownership at the Land Department, and the amount stated in it must cover the actual price of the unit. If a price adjustment increases the purchase price, additional funds will need to be remitted and a new FET obtained covering the full amount.

What to Check and What to Watch Out For

• Which measurement methodology is used for the stated area (saleable or usable) and whether the figure in the contract matches the future unit title.
• Whether a price adjustment clause exists and whether it operates in both directions (additional payment and refund).
• What the tolerance threshold is and whether you have the right to terminate the contract if the deviation exceeds that threshold (for example, more than 5%).
• How the balcony, terrace and the area occupied by the outdoor compressor unit are calculated.
• Whether the availability of space within the 49% foreign ownership quota has been confirmed specifically for your area.
• Whether the amount of the remitted funds and the FET form is sufficient to cover the final (adjusted) price.
• Request the developer's final measurement plan before signing the handover acceptance document and registering title.