Stamp Duty is one of those taxes that lands quietly. There's no invoice from the Revenue Department, no monthly filing to remind you it exists. It's due the moment you sign certain contracts and if you don't pay within 15 days of signing, the surcharge structure escalates fast.
Most businesses in Thailand encounter it regularly without necessarily knowing which of their documents are taxable or what the correct amount should be. This article covers the instruments that trigger Stamp Duty, the rates by document type, who bears the liability, and what it costs to pay late.
What Stamp Duty Is
Stamp Duty is a tax on the execution of specific legal instruments, meaning it's triggered by the act of signing, not by a transaction being completed or a payment being made. The tax is governed by the Revenue Code and applies to a defined list of document types. If your document is on that list, Stamp Duty is owed at the moment the document is signed.
One consequence of this is that an unsigned document carries no Stamp Duty liability. The obligation only attaches when the instrument is executed.
Stamp Duty is generally owed on the instrument at the point of signing, regardless of whether the underlying transaction ultimately proceeds. That said, the Revenue Code (Section 122) provides a mechanism to claim a refund of overpaid duty: if, on the termination of a contract, the duty that was paid turns out to exceed what was actually owed — for example, on a hire-of-work contract stamped on an estimated remuneration that came in lower — a refund claim can be submitted to the Revenue Department.
Which Instruments Are Taxable
The Revenue Code sets out 28 instrument types subject to Stamp Duty. In practice, the ones that come up most often for private businesses are:
- Lease agreements on land, buildings, or other constructions
- Loan agreements and overdraft facilities
- Hire of work agreements (service contracts)
- Share transfer agreements
- Hire purchase agreements
- Company incorporation documents (MoA, AoA) and amendments
- Real estate and vehicle transfer receipts
- Powers of attorney, proxies, letters of credit, insurance policies, bills of exchange, cheques, promissory notes, and share certificates
If your document type is not on the statutory list, it is not subject to Stamp Duty regardless of its value. The tax does not apply to employment contracts, ordinary purchase orders, or most operational agreements.
Rates by Instrument Type
The table below covers the main instrument types and their applicable rates. Party liable refers to the party who has the primary legal obligation to pay the duty, though the parties may agree between themselves to split it.
| Instrument | Rate / Amount | Party Liable |
|---|---|---|
| Lease agreement (land, building, other constructions) | 0.10% of total rent | Lessor |
| Hire of work agreement | 0.10% of contract value | Contractor |
| Hire purchase agreement | 0.10% of contract value | Property owner |
| Share transfer agreement | 0.10% of value | Transferor |
| Loan / overdraft agreement | 0.05% (max ฿10,000) | Lender |
| Letter of credit | 0.20%–0.30% | Issuer |
| Insurance policy | 0.05%–0.40% | Insurer |
| Real estate transfer receipt | 0.50% of value | Seller |
| Vehicle transfer receipt | 0.50% of value | Seller |
| Memorandum of Association (MoA) | ฿200 (flat) | Promoters |
| Articles of Association (AoA) | ฿200 (flat) | Director(s) |
| Amendment to MoA or AoA | ฿50 (flat) | Director(s) |
| Partnership agreement | ฿100 (flat) | Partners |
| Power of attorney (general) | ฿30 (flat) | Grantor |
| Power of attorney (specific act) | ฿10 (flat) | Grantor |
| Proxy for voting at a meeting | ฿20–฿100 | Grantor |
| Government bond | 1% of value | Holder |
| Bill of exchange / promissory note | ฿3 (flat) | Issuer |
| Cheque | ฿3 (flat) | Drawer |
| Share certificate | ฿5 (flat) | Holder |
For lease agreements specifically, the Stamp Duty is calculated on the total rent over the entire lease period.
When Payment Is Due
Stamp Duty is due on the date the instrument is signed. You then have 15 days to pay it without incurring a surcharge. Payment can be made at any Revenue Department office or online for certain instrument types.
The method of payment depends on the nature of the contract, not just its value. There are three routes:
Adhesive stamps — for traditional paper instruments below the value thresholds below. Prepaid stamps are affixed directly on the document.
Form Or.Sor.4 — historically used for cash payment at an area Revenue Department office, this form can now also be filed online to pay digitally, making it the practical alternative to adhesive stamps for paper contracts. It is the only permitted method (adhesive stamps are not accepted) for lease agreements, hire-of-work agreements, and loan agreements with a value of ฿1,000,000 or more.
Form Or.Sor.9 — for contracts drafted, reviewed, and signed entirely using digital signatures via an electronic platform. If your contract is an e-instrument, this is the correct form, filed through the Revenue Department's online platform.
What Late Payment Costs
The surcharge structure is steep relative to the original duty and escalates in two steps:
| Payment date (from signing) | Surcharge |
|---|---|
| Within 15 days | None |
| 15 days to 90 days | 2 times the duty, minimum ฿4 |
| 90 days or more | 5 times the duty, minimum ฿10 |
Under Section 113 (voluntary late payment), the minimum surcharge is ฿4 for the 15-to-90-day window and ฿10 beyond 90 days, floors that are only relevant for very low-value instruments such as a cheque or promissory note (฿3 duty each). For percentage-based instruments on any meaningful contract value, the multiplier calculation will always exceed those floors.
A practical example: a lease agreement on a 3-year office rental at ฿80,000 per month carries total rent of ฿2,880,000. Stamp Duty at 0.10% is ฿2,880. Paid after 90 days, the surcharge is 5 times that — ฿14,400 — on top of the original ฿2,880.
Common Mistakes
- Signing and filing without paying. Many companies sign contracts, file copies internally, and never think about Stamp Duty. The clock starts at signature, not at the point the contract is used or enforced.
- Calculating the lease base incorrectly. Stamp Duty on a lease is calculated on total rent for the full term, not one month. A one-year lease at ฿50,000/month has a base of ฿600,000 and duty of ฿600, not ฿50.
- Missing the 15-day payment window.
- Overlooking instruments in loan renewals or lease extensions. Each new agreement or amendment is a fresh instrument and may trigger a new Stamp Duty obligation, depending on the document's structure.
Stamp Duty is a straightforward tax when you know which documents it applies to and when payment is due. The surcharge structure means that missing the 15-day window on even a mid-sized contract can turn a minor liability into a real cost. The proper compliance approach is therefore to review potentially taxable instruments as part of your standard contract-signing process.