Tax Guide for Businesses in Thailand

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.

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.

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.

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.

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.