Accounting and tax fees in Thailand: monthly bookkeeping, annual audit and what drives the price
Short answer
Monthly accounting for a small Thai company with modest transaction volume commonly falls in the low thousands of baht per month and rises with the number of documents, VAT registration, payroll headcount and the use of foreign currency. Annual work — financial statements, the corporate income tax return and the statutory audit signed by a licensed auditor — is quoted separately and is due even for a dormant company. Because Thai law requires monthly filings for VAT, withholding tax and social security on fixed deadlines, the real cost of cheap bookkeeping usually appears as penalties and surcharges rather than as a higher invoice.
Price and timeline table
| Item | Service fee range (estimate) | Timeline | Notes |
|---|---|---|---|
| Monthly bookkeeping, low volume (up to ~50 documents) | THB 3,000–6,000 / month | Delivered monthly against the filing calendar | Assumes documents arrive complete and on time |
| Monthly bookkeeping, medium volume with VAT | THB 6,000–15,000 / month | Monthly | Includes VAT return preparation and withholding tax filings |
| Payroll and social security | Per-employee monthly fee | Monthly, aligned to the payroll date | Covers payslips, contributions and the annual employee return |
| Annual financial statements and corporate income tax return | Annual fee by company size | Prepared after the year end, before the statutory deadlines | Filed with both the Revenue Department and the DBD |
| Statutory audit by a licensed auditor | Quoted by auditor, scales with turnover and complexity | Several weeks after the accounts are closed | Required for every registered Thai company, including dormant ones |
| Catch-up bookkeeping for prior periods | Quoted after a document review | Depends on the backlog | Penalties and surcharges for late filing are additional |
These figures are budgeting estimates, not binding quotations. Government fees are separate from the service fee, and the applicable price is confirmed in a written quotation after the documents have been reviewed.
What makes the price differ
Document volume, not revenue
A company with high turnover but ten invoices a month is cheaper to service than a retail business with hundreds of small receipts. Pricing follows the number of items to be recorded and reconciled.
VAT registration
Once registered, a monthly VAT return is due whether or not there was any activity, and input tax documents must be checked for validity before they can be claimed.
Payroll headcount
Every employee adds withholding tax and social security work each month plus annual returns, so payroll is normally priced per head rather than bundled.
Foreign currency and cross-border flows
Overseas invoices, exchange differences and transactions with related parties add reconciliation work and can bring documentation duties that a purely domestic business does not have.
How the work actually runs
1. Onboarding and opening balances
The accountant reviews the affidavit, VAT registration, the previous year's financial statements and the chart of accounts, then sets opening balances so the new period reconciles.
2. Monthly document handover
Sales invoices, purchase tax invoices, receipts, bank statements and payroll data are delivered on an agreed cut-off date each month.
3. Recording and reconciliation
Entries are posted, bank balances reconciled and input tax documents checked for validity before anything is claimed.
4. Monthly filings
VAT, withholding tax and social security returns are prepared and submitted by their statutory deadlines, with the payment amounts confirmed to the client first.
5. Management reporting
A monthly trial balance and summary are issued so the directors can see profitability and tax exposure while there is still time to act.
6. Year-end closing and audit support
Accounts are closed, financial statements prepared, and the auditor's requests answered until the audit report is signed.
7. Annual filings
The audited statements and the corporate income tax return are filed with the Revenue Department and the Department of Business Development within the statutory windows.
Documents to prepare
- Company affidavit, VAT certificate (Phor Phor 20) and the tax identification number
- All sales invoices and receipts issued during the month, in sequence
- Purchase tax invoices and expense receipts showing the company name and tax ID
- Full bank statements for every account, including those rarely used
- Payroll records, employment contracts and social security registration data
- Prior-year audited financial statements when switching accounting firms
Mistakes that make you pay twice
Assuming a dormant company has nothing to file
A registered company with no activity still has to prepare audited financial statements and file an annual return. Skipping them creates penalties that compound quietly for years.
Claiming input tax on invalid documents
A tax invoice missing the buyer's name, address or tax ID cannot support an input tax claim. Correcting this at audit is far more expensive than checking it at receipt.
Paying personal expenses from the company account
Expenses without a business purpose are disallowed, increase taxable profit and raise the risk of a wider examination of the accounts.
Delivering documents after the cut-off
Late documents compress the work into the days before a statutory deadline, which is exactly when filing errors and surcharges occur.
Frequently asked questions
- What does a Thai accounting firm actually do each month?
- It records every sale and purchase, reconciles the bank accounts, checks that input tax documents are valid, prepares and files the VAT return, the withholding tax returns for payments to suppliers and employees, and the social security contribution, then issues a trial balance so the directors can see the position. The visible output is a set of filings, but most of the effort is in verifying source documents, because that is what determines whether the filings survive a later examination.
- Why is audit quoted separately from bookkeeping?
- Thai law requires the annual financial statements of a registered company to be examined by a licensed auditor who must be independent of the person preparing the accounts. The same firm therefore cannot both keep the books and sign the audit report on them. Practically, the accounting firm prepares the statements and coordinates with an independent auditor, whose fee is quoted on turnover, transaction complexity and the state of the records.
- Does a company with no income still need an accountant?
- Yes. Filing duties attach to registration, not to activity. A dormant company must still submit audited financial statements, a corporate income tax return, and — if it is VAT registered — a monthly VAT return showing nil. The fee for a dormant company is low, but the penalties for years of non-filing are not, and they must all be cleared before the company can be closed properly.
- How much does it cost to fix several years of missing accounts?
- It is quoted only after reviewing what exists, because the work depends on whether bank statements and invoices are recoverable. Expect three cost components: reconstructing the bookkeeping, the audit fees for each outstanding year, and the statutory penalties and surcharges for late filing. The surcharge element grows with time, so the cost of acting this quarter is always lower than the cost of acting next year.
- Is hiring a firm cheaper than employing an in-house accountant?
- For most small and medium companies, yes, because an outsourced fee covers a team with a licensed bookkeeper, filing software and coverage during holidays, at less than a full salary plus social security. An in-house hire becomes worthwhile when transaction volume is high, when management needs daily figures, or when the business handles cash operations that need constant control. Many companies run a hybrid: an in-house clerk for daily entry, an external firm for filings and year-end.
- What is the difference between tax planning and tax avoidance?
- Lawful planning means using the deductions, allowances and incentives that the law actually provides — documenting expenses correctly, timing capital purchases, and applying available exemptions — and being able to show the underlying evidence. What creates exposure is inventing expenses, issuing documents that do not reflect a real transaction, or moving profit without substance. The test is simple: if the arrangement cannot be explained with documents to an examiner, it is not planning.
- Can accounting documents be kept electronically?
- Electronic tax invoices and receipts are permitted under the Revenue Department's e-Tax Invoice and e-Receipt framework, subject to registration and to the technical requirements for issuing and storing them. Scanned copies of paper documents are useful for workflow but do not automatically replace the retention duty for originals, so confirm with your accountant which of your document types are formally in the electronic system and which are not.
- When must a company register for VAT?
- Registration is mandatory once annual taxable turnover passes the statutory threshold, and it can be done voluntarily before that, which many companies do because their business customers expect a tax invoice. Registration brings a monthly filing duty and an address inspection by the Revenue Department, so the decision should account for both the credibility benefit and the ongoing compliance load.
- What happens if a monthly filing is late?
- A surcharge accrues on the tax due and a fine applies for the late return itself, separately for each filing type missed. A single late month is inexpensive to fix; a pattern of them attracts attention and makes a full examination more likely. If a deadline has already passed, filing immediately limits the surcharge, because it is calculated on time elapsed.
- How do I change accounting firms cleanly?
- Ask the outgoing firm for the general ledger, the trial balance, the filed returns with their receipts, and the last audited statements, and confirm which periods are fully filed. The incoming firm sets opening balances from those documents. The safest point to change is straight after a year end, because it avoids splitting one financial year between two sets of records.
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Other cost guides
Official sources — accounting, tax, social security
The information on this page follows the official sources below. Always check the latest version before you file.
- กรมสรรพากร — ประมวลรัษฎากร ภาษีเงินได้ VAT— Revenue Department
- สำนักงานประกันสังคม— Social Security Office
- กรมพัฒนาธุรกิจการค้า — จดทะเบียนนิติบุคคล— Department of Business Development
- สำนักงานคณะกรรมการกฤษฎีกา — ฐานข้อมูลกฎหมายไทย— Office of the Council of State
- สำนักงานคณะกรรมการส่งเสริมการลงทุน (BOI) / LTR Visa— Thailand Board of Investment
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