Reviewed by ThaiLawOnline, a licensed Thai law firm practising in Thailand since 2006. Thai lawyer of record: Wichuda Atthamethakon, LL.M., Thai Bar Licence 3149/2556.
Last updated on September 5, 2026
Corporate income tax (ภาษีเงินได้นิติบุคคล, phasi ngoen dai nitibukkhon, abbreviated CIT) is the tax a company limited, partnership or other juristic person pays on its net profit under the Revenue Code. The standard rate is 20% of net profit after deductible expenses, with lower bands for small companies and full or partial exemption for BOI-promoted activities. It is paid in two instalments and enforced by the Revenue Department, a separate authority from the DBD. Every Thai company owes a return, even one that made no profit or never traded.
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Rates and how profit is computed
The general rate is 20% of net profit, being revenue less the expenses the Revenue Code allows: ordinary business costs, depreciation at prescribed rates, donations up to 2% of net profit, and enhanced deductions for research and development. Losses can be carried forward for 5 years. A company whose paid-up capital does not exceed 5,000,000 baht and whose revenue does not exceed 30,000,000 baht in the year is an SME and pays on a sliding scale.
| Net profit band (SME) | Rate | Condition |
|---|---|---|
| First 300,000 baht | Exempt | Paid-up capital not over 5,000,000 baht |
| 300,001 to 3,000,000 baht | 15% | and revenue not over 30,000,000 baht |
| Above 3,000,000 baht | 20% | Same as the general rate |
A company promoted by the BOI is exempt on the promoted activity for the period in its certificate, from 3 to 13 years depending on category. Very large multinational groups have been subject since 2025 to a 15% global minimum top-up tax, which does not concern an ordinary Thai company.
Filing and paying in practice
Two returns are due each year. The half-year return, form PND 51, is filed within 2 months of the end of the first 6 months of the accounting period and pays tax on half of the estimated profit for the year; an estimate that falls short of the actual profit by more than 25% without good reason attracts a surcharge on the shortfall. The annual return, form PND 50, with the audited financial statements, is filed within 150 days of the year end, which for a December year end means by the end of May.
Corporate income tax is only one of the taxes the company handles. VAT is filed monthly, and withholding tax must be deducted from most payments the company makes, typically 3% on services, 5% on rent and 10% on dividends, and remitted by the 7th of the following month. The common mistake is to leave all of this to an accountant without checking that the returns were filed; the director signs the accounts and carries the exposure.
Penalties and the dormant company problem
Late payment carries a surcharge of 1.5% a month on the unpaid tax, and a late or missing return attracts a fine on top; where books are missing the Revenue Department assesses tax on its own figures, enforceable against the company’s bank accounts and property. Deliberate evasion is a criminal offence for the company and usually for the director responsible.
A company that stops trading but is never dissolved still owes a PND 50 and an audit every year. When the owner eventually wants to close it, the Revenue Department reviews the missing years before it issues tax clearance, and every unfiled return has to be prepared and paid with surcharges. That is why dissolution of a neglected company costs more than compliance would have.
Frequently asked questions
What is the corporate income tax rate in Thailand?
20% of net profit. A small company with paid-up capital of not more than 5,000,000 baht and revenue of not more than 30,000,000 baht pays nothing on the first 300,000 baht of profit, 15% on profit up to 3,000,000 baht and 20% above that. BOI-promoted activities can be exempt for 3 to 13 years.
When is corporate income tax due in Thailand?
The annual return, PND 50, is due within 150 days of the end of the accounting period, so by the end of May for a calendar-year company. A half-year return, PND 51, is due within 2 months of the end of the first half of the year and pays tax on half the estimated annual profit.
Does a dormant company in Thailand have to file tax returns?
Yes. A registered company must file PND 50 with audited accounts every year whether or not it traded, and PND 51 at the half year. Missing returns accumulate fines and surcharges and must all be filed before the Revenue Department will clear the company for dissolution.
See also: VAT, Tax identification number, Company limited, BOI, corporate tax in Thailand and can you go to jail for unpaid taxes in Thailand.
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