Companies and juristic partnerships registered with the Department of Business Development receive a 13-digit juristic person registration number, which is used as the taxpayer identification number. The old advice that every company must apply for a separate taxpayer identification number should therefore no longer be followed. Having the number, however, does not mean that the company is registered for VAT or that its electronic filing access has been fully activated.
A business person who sells goods or provides services in the ordinary course of business and whose revenue exceeds 1.8 million baht a year must apply for VAT registration within 30 days from the date the revenue exceeds that threshold, according to Revenue Department guidance. Some businesses are exempt from VAT or fall under specific business tax, so the type of revenue must be checked before counting toward the threshold. How revenue is counted toward the threshold, voluntary registration, and the monthly obligations after registration are explained in our guide to VAT registration (Thai).
A business that has not yet reached the threshold may, in some cases, apply for registration before commencing business where it has a business plan and evidence of preparations to carry on the business. It should, however, weigh the benefit of recovering input tax against the burden of issuing tax invoices, filing the P.P. 30 return, and preparing reports every month. VAT registration is not a seal of credibility that comes free of compliance costs.
| Event | System to prepare | Key evidence |
|---|---|---|
| Paying salaries | Payroll, withholding tax, and social security data | Employment contracts, time records, payslips, and transfer records |
| Paying service fees, rent, or royalties | Classify the type of income, the withholding rate, and the correct withholding tax return for the type of recipient | Contracts, invoices, withholding tax certificates, and remittance records |
| Selling goods or services within the VAT system | Document numbering, tax invoices, the output tax report, and the P.P. 30 return | Purchase orders, delivery notes, tax invoices, and payment receipts |
| Buying goods or services | Verify the seller’s name, address, and taxpayer identification number, and the entitlement to credit input tax | Full tax invoices, receipt of the goods or services, and payment records |
| Receiving services from abroad | Analyze withholding tax under Section 70, VAT on the P.P. 36 return, and the double tax agreement | Contracts, the service provider’s residence, the nature of the work, and remittance records |
Monthly returns arise when there are transactions, such as paying income subject to withholding tax, being a VAT registrant, or receiving services from abroad. Returns for the accounting period, such as the P.N.D. 51 and P.N.D. 50, arise from the entity’s status and its accounting period. A company or juristic partnership whose first accounting period is shorter than twelve months is not required to file the P.N.D. 51 for that period (Section 67 bis, paragraph three, of the Revenue Code), but must still file the P.N.D. 50 at the end of the period. Even in a month with no income, some returns may still have to be filed depending on the company’s registration status.
Official sources (in Thai): Revenue Department — use of the 13-digit taxpayer identification number, persons required to register for VAT and the time limit, list of tax return forms, and Department of Business Development — starting a business. Information verified on 27 June 2026 (B.E. 2569).
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