Tax Penalties and Surcharges in Thailand: How They Are Calculated and How to Reduce Them

The 4 types of amounts demanded are not the same thing

Key rates that are often confused

• Section 22: Where a return was filed but was incorrect or incomplete and an assessment is made, the statutory penalty is generally 1 times the additional tax payable (the Revenue Department’s English translation of the Revenue Code calls this a “fine”).
• Section 26: Where no return was filed and an assessment is made, the statutory penalty is 2 times the tax payable.
• Section 27: A surcharge of 1.5% per month or part of a month on the tax shortfall, generally calculated from the day after the deadline until the date of payment, and capped at the amount of tax payable or remittable under the conditions of the section.
• VAT, Sections 89 and 89/1: Penalties and surcharges depend on the nature of the violation, such as failing to file a return, underpaying, or issuing incorrect tax invoices, so they must be calculated from the facts month by month.

Correcting on your own before an audit usually matters more than explaining afterward

Revenue Department Order No. Tor.Por. 81/2542, as amended by Revenue Department Order No. Tor.Por. 369/2569 (in force from 3 July 2026, B.E. 2569), sets out the criteria for waiving or reducing penalties. The assessment official may waive or reduce a penalty only where the official considers that the taxpayer had no intention of evading tax and cooperated fully with the audit and inquiry. As a rule, the request must be made in writing and filed before the assessment official issues the notice of assessment. The outcome also depends on when the taxpayer filed and paid on its own initiative, whether a written warning or a written audit summons had already been received, and whether the violation was a failure to file or an underpayment. A reduction is therefore neither a single rate nor an automatic entitlement.

1. Stop any violation that is still recurring, and gather the returns for every month or period concerned.
2. Recalculate the principal tax from the actual documents, and reconcile it with the tax already paid.
3. Check whether to file an ordinary return, an additional return, or a petition, and if a petition, which type.
4. Calculate penalties and surcharges separately for each month; do not combine the amounts and apply a single rate.
5. Pay and file promptly once the information is complete, and keep the receipts and evidence of filing.

What a penalty reduction request should prove

A good request points to facts rather than simply asking for sympathy. Documents that carry weight include a timeline of events, the cause of the violation, how it was detected internally, the system changes made, the new person responsible, and evidence of cooperation with the officials. Where a point of law is open to more than one interpretation, attach the relevant provisions, rulings, or court judgments.

• Whether the violation is a first occurrence or a repeat, and whether a system to prevent recurrence is now in place
• To what extent the taxpayer disclosed the information and paid before being detected
• Whether there was an intention to evade tax, or an error arising from complex facts and law
• Whether each component of the assessment is correct, or whether there are still grounds to appeal the principal tax
• At which stage the request falls within the authority of the officials, the Commission of Appeal, or the court

Checklist before accepting an assessment

• The due date is correct, taking into account any holidays and applicable extension announcements
• Parts of a month and the payment date are counted correctly
• The calculation base does not include the penalty, so that no surcharge is calculated on the penalty
• Input tax, tax credits, and withholding tax already paid have all been deducted
• The penalty rate matches the section and the circumstances of that return
• Whether the time limit for an appeal or petition is still open, and how payment will affect your rights

Official sources: Revenue Code, Sections 14–27 (Thai), examples of calculating VAT penalties and surcharges (Thai), Revenue Department Order No. Tor.Por. 81/2542, as amended by Tor.Por. 369/2569 (Thai), and Departmental Instruction No. Por. 163/2567 on counting time periods for calculating penalties and surcharges, which repealed Por. 117/2545 (Thai). Information checked on 16 October 2026 (B.E. 2569).