Tax Guide for Businesses in Thailand

Business tax in Thailand is not a single annual payment. A company may have corporate income tax, value added tax, withholding tax and payroll reporting obligations running on different calendars, while some activities or documents can also trigger specific business tax or stamp duty. The right setup depends on the legal entity, activities, customers, employees, cross-border payments and any investment privileges.

This guide is for owners and managers of Thai companies who need to understand what to register for, what their accountant should be filing and which records management must review. It is a practical planning guide, not a substitute for advice on a particular transaction. Check the latest forms, filing calendar and announcements with Thailand's Revenue Department before acting.

Set up the tax position before trading

Start with the actual transaction flow, not only the company registration certificate. List what the business will sell, where goods or services are supplied, who will invoice customers, which entity will employ staff and whether money will be paid to related companies or overseas suppliers. Those facts determine which taxes, registrations and evidence apply.

Decisions to confirm at the outset

• Taxpayer and accounting period: confirm which Thai or foreign entity earns the income, its tax identification details and its financial year.
• VAT status: decide whether registration is compulsory, voluntary or unavailable because the activity is exempt or subject to another regime.
• Withholding responsibilities: map common outgoing payments such as services, rent, interest, royalties, dividends and payments abroad.
• Employees: establish payroll withholding, employee certificates and employer reporting from the first payroll.
• Books and documents: configure invoices, expense approvals, tax certificates and accounting records before the first transaction.
• Special circumstances: identify BOI promotion, related-party dealings, cross-border services, imports, exports or sector-specific taxes early.

Use a Thai accountant or tax adviser to confirm the treatment of unusual transactions. Commercial labels are not decisive: a payment called a “management fee”, for example, must still be analysed by its real nature, recipient and supporting documents.

Corporate income tax

Corporate income tax applies to Thai companies and juristic partnerships and can also apply to foreign companies carrying on business in Thailand or deriving specified Thai-source income. The Revenue Department's published general rate is 20% of net profit, but reduced rates, exemptions and special bases may apply to qualifying taxpayers or activities. Confirm the current rule for the relevant accounting period rather than assuming a headline rate applies to every business.

Taxable profit is not necessarily the same as the profit shown in management accounts. Revenue and expenses must be adjusted under the Revenue Code. Expenses should be connected with the business, properly evidenced and not fall within a prohibited or restricted category. The Revenue Department lists examples including depreciation, bad debts, certain donations and tax losses, each subject to its own conditions and limits.

Main corporate filings

1. Half-year return: a company generally estimates annual net profit and files Form P.N.D. 51, with any payment due, within two months after the end of the first six months of its accounting period.
2. Annual return: Form P.N.D. 50 is generally due within 150 days after the accounting-period closing date.
3. Reconciliation: accounting profit is reconciled to taxable profit, including non-deductible costs, capital allowances, incentives, withholding credits and carried-forward losses where permitted.

Forecasting matters because a half-year estimate that is materially low without reasonable cause can create exposure. Review the forecast with current trading results, not a copy of last year's figures. Keep schedules supporting revenue recognition, provisions, fixed assets, related-party charges and claimed incentives.

Read the Revenue Department's corporate income tax overview.

Value added tax

A person or entity that regularly supplies goods or services in Thailand is generally required to register for VAT when annual turnover exceeds THB 1.8 million, subject to exemptions and special rules. The Revenue Department states that registration should be made before business begins where required or within 30 days after income reaches the threshold. Importers may incur import VAT regardless of registration, and certain businesses fall under specific business tax rather than VAT.

The current general VAT rate is 7%. This is a reduced rate that is extended by time-limited legislation; the Revenue Department's decree index identifies Royal Decree No. 807 B.E. 2569 as extending the 7% rate through 30 September 2027. Always check the current rate for the transaction date. Zero-rating can apply to qualifying exports and specified international transactions, but zero-rated and exempt supplies are not the same and require different evidence.

How the monthly calculation works

A VAT registrant normally compares output VAT charged on taxable sales with creditable input VAT supported by valid tax invoices. The difference is paid or, where permitted, carried forward or claimed. Not every amount labelled VAT is recoverable: the supplier's status, invoice details, business purpose and restriction rules matter.

• Issue the correct tax invoice when the tax liability arises.
• Check supplier invoices before treating VAT as input tax.
• Maintain output-tax, input-tax and goods or raw-material reports where required.
• Reconcile the VAT return to sales, purchases, bank receipts and the general ledger.
• File a return for each tax month even when there were no sales, where the law requires a nil return.

The statutory VAT return is generally filed by the 15th day of the following month, although online filing arrangements and official extensions can change practical deadlines. Cross-border services can create a recipient-side VAT obligation, commonly reported on Form P.P. 36, even when the overseas supplier does not charge Thai VAT.

Check the Revenue Department's VAT guidance and the Revenue Code provisions on registration and tax invoices.

Withholding tax on payments

Thai businesses often act as tax collectors when they make specified payments. The payer must determine whether withholding applies, deduct the correct amount, remit it using the appropriate return and give the recipient a withholding tax certificate. The recipient normally uses the amount withheld as a credit, subject to the applicable rules.

The rate depends on the nature of the payment, the legal and tax status of the recipient, whether the recipient has a permanent establishment in Thailand and, for cross-border payments, whether a double tax agreement changes the domestic result. Published examples include service and professional fees, rent, advertising, interest, royalties, dividends and prizes, but the correct classification must be checked for the actual contract and recipient.

A reliable payment control

1. Classify the payment from the contract, invoice and work performed.
2. Verify the recipient's name, tax identification number, residence and entity type.
3. Check the domestic rate and any treaty claim or exemption documentation.
4. Calculate and deduct the tax before releasing payment.
5. Issue the certificate and include the payment on the correct monthly return.
6. Reconcile certificates and returns to the payable ledger and bank.

Do not wait until year-end to reconstruct withholding. Missing certificates or incorrect payee details cause problems for both parties and can delay tax-credit claims. For payments abroad, also consider VAT, treaty residence evidence and whether the arrangement creates a taxable presence or transfer-pricing issue.

Find Revenue Department withholding-tax forms.

Payroll withholding and employee reporting

An employer must calculate withholding on employment income using the employee's taxable pay and available information, remit it through the appropriate payroll return and provide the required annual certificate. Bonuses, benefits, allowances, director remuneration, termination payments and expatriate packages may need separate analysis rather than being treated as ordinary net salary.

• Obtain complete employee tax and allowance declarations.
• Keep payroll, employment-contract and benefit records aligned.
• Reconcile payroll expense, withholding, bank payments and annual certificates.
• Review internationally mobile employees for Thai residence, source and treaty issues.
• Coordinate tax reporting with social-security and work-authorisation duties, which are separate obligations.

Employment tax rates and personal circumstances can change. Use the current Revenue Department rules for each tax year and obtain advice for split payrolls, equity awards or employees working across borders.

Specific business tax and stamp duty

Not every business is dealt with only under corporate income tax and VAT. Specific business tax applies to categories listed in the Revenue Code, including specified banking, finance, securities, life-insurance, pawnbroking and commercial immovable-property activities. The tax base and rate depend on the activity. A business with a potentially covered transaction should confirm whether it needs registration, monthly returns and gross-receipts records.

Stamp duty is charged on instruments listed in the Stamp Duty Schedule rather than on every commercial transaction. Examples can include leases, share transfers, powers of attorney and certain financing instruments. Liability, rate and timing depend on the document and how or where it is executed. Include a stamp-duty review in contract and closing checklists instead of discovering it when a document is needed as evidence.

Review the Revenue Code chapter on specific business tax and the Revenue Department's stamp-duty overview.

Cross-border and related-party transactions

International transactions require more than checking whether an invoice came from overseas. Consider Thai-source income, withholding tax, VAT on imported services, customs and import VAT on goods, permanent-establishment exposure, treaty relief and the place where services are performed and used.

Transactions between related parties should be priced on an arm's-length basis and supported by contemporaneous records. Keep agreements, allocation methods, calculations and evidence of the commercial benefit received. The documentation needed depends on the group's facts and the current transfer-pricing rules; larger or connected groups may have specific disclosure obligations.

BOI promotion or another incentive may reduce tax on promoted activities, but conditions, separate accounts and non-promoted income still need attention. Do not treat company promotion as a blanket exemption for every transaction.

Read the Revenue Department's transfer-pricing material and its guide for foreign companies.

Build a practical filing calendar

Create one calendar that includes preparation, management review, filing and payment dates. The deadline is not the day to start assembling the figures.

• Monthly: payroll withholding, other withholding returns, VAT or specific business tax where applicable, plus reconciliations and payment evidence.
• Half-year: corporate income tax forecast and P.N.D. 51 preparation.
• Annual: audited accounts, corporate income tax return, employee certificates and other statutory submissions that apply to the entity.
• Transaction-based: VAT registration threshold monitoring, new branches, cross-border payments, contracts requiring stamp duty, dividends, restructurings and asset disposals.
• Change-based: updates to registered details, accounting period, business activities or cessation.

Use the Revenue Department's live tax calendar and e-filing system to confirm the exact deadline and form. Weekend rules, electronic-filing extensions and temporary relief can change the practical date.

Check the Revenue Department tax calendar and current announcements.

Records and controls that reduce tax risk

Good compliance depends on evidence. Keep accounting records, tax invoices, withholding certificates, contracts, bank evidence, customs documents, payroll support and filed returns in an organised system for the legally required period. VAT rules generally require specified invoices, reports and supporting documents to be retained for at least five years, but other laws or an active assessment can require longer retention.

Monthly management review

• Reconcile revenue to invoices, receipts, VAT and bank deposits.
• Reconcile purchases and expenses to supplier documents and withholding.
• Review unusual, high-value, related-party and overseas transactions before filing.
• Track VAT turnover against the registration threshold if not registered.
• Compare filed returns and payments with the ledger and keep submission receipts.
• Maintain an issues log with an owner and correction deadline.

If an error is found, investigate promptly. The correction route depends on the tax, period and whether additional tax or a refund is involved. Do not simply overwrite filed figures in the accounting system without preserving a clear audit trail.

What to do next

1. Map the company's activities, transaction flows, employees and overseas payments.
2. Confirm tax identification, VAT or specific-business-tax registrations and the accounting period.
3. Assign an accountant and an internal director or manager who remains accountable for review.
4. Create the monthly, half-year and annual calendar with preparation dates before statutory deadlines.
5. Test invoice, withholding, payroll and record-retention controls using real transactions.
6. Ask for written advice before a material unusual, related-party or cross-border transaction.

Tax rates, forms, incentives and filing arrangements change. Recheck the official Revenue Department source for the relevant period and seek professional advice where the facts are material or uncertain.