How is an architect’s professional fee different from hire-of-work on the 50 Tawi?

The 3% rate is the same, but professional fees fall under Section 40(6) while ordinary hire-of-work is 40(7)–(8); pick the matching income type on the 50 Tawi so the filing is correct.

What withholding tax rate applies to a Architect?

Generally 3% when the client is a juristic person. For example, a ฿80,000.00 fee is withheld ฿2,400.00, so you receive ฿83,200.00.

Does a Architect issue the 50 Tawi themselves?

No. On your sales invoice the client withholds and issues the 50 Tawi to you; your job is to keep it as evidence to credit on your annual return.

Freelancer guide

Invoicing & tax for a Architect in Thailand

Architectural design and professional services are “professional fees” under Section 40(6), withheld at 3%; above ฿1.8M/year you must register for VAT and add 7%.

By the BillsOS team · Updated 8 Jun 2026

A worked example

Say you are a Architect invoicing a corporate client ฿80,000.00 for your work. The income type is “Professional fees”, withheld at 3%, and since you are VAT-registered you add 7% VAT. The figures below come straight from the BillsOS engine.

Fee (before VAT)	฿80,000.00
VAT 7%	฿5,600.00
Total invoiced	฿85,600.00
Less withholding tax 3%	-฿2,400.00
Net the client pays (QR amount)	฿83,200.00

The client withholds ฿2,400.00 and transfers you ฿83,200.00, handing you a 50 Tawi certificate as evidence.

Who withholds: On your own sales invoice you are the payee. Your client (the payer) is the one who withholds the tax and issues you the 50 Tawi — you do not issue it yourself.

What to watch for in this trade

Architect fees sit under Section 40(6) professional income (distinct from ordinary hire-of-work even though both withhold 3%), so the 50 Tawi must tick the right income box.

Documents you’ll need

Tax invoice / receipt — being VAT-registered, you issue a tax invoice with 7% VAT
Quotation and invoice — before the work and when you bill
50 Tawi — received from the client and kept for every job, to credit on your annual return

Tools & guides for this

BillsOS issues invoices and receipts that compute the withholding and 7% VAT for you, with an exact-amount PromptPay QR embedded so the client scans and pays straight into your own account.

Start invoicing as a Architect — free →

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BillsOS only formats and computes documents for you. This is general information, not tax advice — please confirm with the Revenue Department or your accountant.