What Accounting and Tax Filings Does a Small Thai Company Need, and When Should You Hire an Accounting Firm?
Last reviewed: · Reviewed by Mr. Wiwat, Notarial Services Attorney registered with the Lawyers Council of Thailand — view licence
Short answer
Every Thai limited company must keep books, file monthly returns for withholding tax (P.N.D.1, 3, 53), VAT if registered (P.P.30) and social security if it has staff, then close annual financial statements, have them audited by an independent licensed auditor and file the corporate income tax return (P.N.D.50) and financial statements. Hiring an accounting firm makes sense once you have regular transactions, staff or VAT registration and no qualified in-house bookkeeper.
1. Monthly filings at a glance
| Form | What it covers | Usual deadline |
|---|---|---|
| P.N.D.1 | Withholding tax on employee salaries | 7th of next month (paper); later for e-filing |
| P.N.D.3 / 53 | Withholding tax on payments to individuals / companies | 7th of next month (paper) |
| P.P.30 | VAT return, required even with no sales | 15th of next month (paper) |
| S.P.S.1-10 | Social security contributions | 15th of next month |
Deadlines can change by official announcement; e-filing often has an extended date. Always check the current Revenue Department notice.
2. Common withholding tax rates
- Rent: 5%
- Services and professional fees: 3%
- Transport: 1%
- Advertising: 2%
- Interest paid to companies: 1%
Issue a withholding tax certificate (50 Tawi) to the payee every time you withhold. Missing certificates are one of the most common problems found at year end. Rates for payments to foreign recipients differ and may be affected by tax treaties.
3. Annual cycle: closing, audit and P.N.D.50
- Mid-year: file the half-year estimate (P.N.D.51) within two months after the first six months.
- Year end: reconcile bank, stock, receivables and payables.
- Independent licensed auditor audits the statements. The auditor must be independent from whoever keeps your books.
- Shareholders approve the statements at the annual general meeting.
- File P.N.D.50 within 150 days of year end and submit statements to the Department of Business Development.
4. Do it yourself, in-house accountant or accounting firm?
Do it yourself only if transactions are very few and you understand Thai forms. Mistakes lead to surcharges.
In-house accountant suits companies with high daily volume that need someone on site.
Accounting firm suits most small and foreign-owned companies: a team covers filings, holidays and law changes, and reports in English.
5. Mistakes that cause penalties
- Skipping P.P.30 in months with no sales.
- Accepting invoices without a valid tax invoice format, so input VAT cannot be claimed.
- Mixing personal and company spending.
- Paying foreign suppliers without checking withholding tax and P.P.36.
- Leaving documents until year end.
- Using the same person as bookkeeper and auditor.
Step-by-step table
| Step | What happens | Who |
|---|---|---|
| 1. Initial review | We review your company status, registrations and what has been filed so far. | You + us |
| 2. Scope and quote | Written scope: bookkeeping, filings, payroll, audit coordination. Fees quoted before work starts. | Us |
| 3. Document flow | Agree a monthly cut-off for sales, purchase and bank documents. | You |
| 4. Monthly filings | Prepare and file returns; send you a summary and payment amounts. | Us |
| 5. Year-end close | Prepare statements and coordinate with an independent auditor. | Us + auditor |
| 6. Annual filings | File P.N.D.50 and financial statements; plan the next year. | Us |
Document checklist
- Company affidavit, VAT certificate (P.P.20) and shareholder list.
- Sales invoices and tax invoices issued.
- Purchase invoices and receipts received.
- Bank statements for every company account.
- Payroll records and employee social security details.
- Contracts for rent, loans and major services.
- Prior-year audited statements, if any.
Build your own list: document checklist tool (results are guidance only).
Frequently asked questions
Must a small Thai company be audited every year?
Limited companies generally need an audit by a licensed auditor. Certain very small partnerships have different rules. Ask us to confirm for your entity.
Do I file VAT if I had no sales?
Yes. A VAT-registered company files P.P.30 every month, including nil months.
When must I register for VAT?
When annual taxable revenue exceeds THB 1.8 million, or earlier voluntarily. Use our VAT checker as a guide.
Can you report in English?
Yes. Monthly summaries and explanations are available in English.
Can the same firm do bookkeeping and audit?
No. The auditor must be independent from the bookkeeper. We coordinate with an independent auditor.
What if previous filings were missed?
We review what is missing and prepare a catch-up plan. Surcharges may apply; we do not promise they will be waived.
How are fees set?
By transaction volume, staff count and scope. We send a written quote; government fees and penalties are separate.
Do you work with virtual office companies?
Yes. Many clients registered at a virtual office use us for monthly VAT and accounts.
Where to go next
- Accounting, tax and payroll service
- Virtual office in Thailand: complete guide
- Law firm in Thailand: complete guide
- VAT registration checker
- In-house accountant vs accounting firm
This guide is general information, not legal advice for your specific case. We do not guarantee outcomes or processing times set by government agencies, embassies or foreign recipients. Government and embassy fees are separate from our service fee and are quoted before work starts.
Send your documents for a pre-checkOr email Contact@thainotary.co.th
Key facts at a glance — End-to-end certification and translation
- Service fee
- Contact us for a quote — a firm quote is always given before work starts
- Turnaround
- 1–7 business days by document type and receiving authority
- What you receive
- Properly certified documents plus guidance on the next filing step
- Service coverage
- Nationwide Thailand — courier and fully online intake, no in-person visit required.
Figures above are indicative ranges; the final quote depends on page count, language pair and receiving authority.
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