Thailand corporate income tax 2025: rates, PND 50 and PND 51 deadlines, loss carryforward, and e filing extension

Thailand corporate income tax 2025: rates, PND 50 and PND 51 deadlines, loss carryforward, and e filing extension

Introduction

Getting Thailand corporate income tax 2025 right is mostly about four controls. Know your rate, meet PND 50 and PND 51 deadlines, preserve loss carryforward, and apply the e filing extension correctly. The headline corporate income tax rate is 20 percent, with reduced SME bands where eligibility is met. Annual return PND 50 is due within 150 days of year end, and the half year return PND 51 is due within two months after the first six months. Thailand extends certain e filed returns by 8 additional days through 31 January 2027.

Legal backbone you can cite

• Standard rate and SME bands. The standard CIT rate is 20 percent. SMEs that satisfy paid up capital and annual revenue thresholds are taxed at 0 percent for the first 300,000 baht of net profit, 15 percent from 300,001 to 3,000,000 baht, and 20 percent above 3,000,000 baht.

• Annual filing. PND 50 must be filed within 150 days after the end of the accounting period.

• Half year filing. PND 51 must be filed within two months from the last day of the first six months of the accounting period.

• E filing extension. The Thai Revenue Department has extended the 8 day grace period for e filed tax returns through 31 January 2027.

• Loss carryforward. Net operating losses may be carried forward for five accounting periods.

• Computation and disallowances. Section 65 bis governs computation of net profit and allows depreciation per Royal Decree rules. Section 65 ter lists non deductible expenses.

Thailand corporate income tax 2025 checklist

1) Confirm your rate profile

• Most companies pay 20 percent.

• If you are an SME with paid up capital not exceeding 5 million baht and annual revenue not exceeding 30 million baht, apply the 0 percent, 15 percent, 20 percent bands to the stated net profit thresholds. Document eligibility each year.

2) Calendar statutory returns

• PND 51 half year estimated tax within two months after the end of months 1 to 6 of your accounting period.

• PND 50 annual return within 150 days after year end.

• If you e file, check whether the due date falls during the current 8 day extension window valid through 31 January 2027.

3) Keep loss carryforward usable

Track tax losses and expiry, since losses carry forward five accounting periods and cannot be carried back. Build schedules that link audited financials to the tax computation and Section 65 bis adjustments.

4) Get Section 65 bis and Section 65 ter right

• Apply the depreciation and deductibility rules under Section 65 bis and related Royal Decrees.

• Exclude non deductible items under Section 65 ter such as certain provisions, penalties, and non business expenses.

5) Use the PND 51 safe line to avoid surcharges

Under Section 67 ter, if your PND 51 estimated profit is understated by more than 25 percent of the actual full year net profit without reasonable cause, a 20 percent surcharge applies to the shortfall. Monitor actuals during the year and adjust if new information arises.

6) Budget for interest and surcharge if you slip

Late payment triggers a surcharge at 1.5 percent per month on unpaid tax. Where an extension to pay is officially granted, the surcharge rate can be 0.75 percent per month. These surcharges are separate from any Section 67 ter 20 percent underestimation surcharge.

7) Watch the 2025 top up tax for large MNEs

From 1 January 2025, Thailand implements the OECD 15 percent global minimum tax. This does not change the 20 percent standard CIT computation, but MNE groups meeting the 750 million euro threshold should align their CIT and Pillar Two data to avoid inconsistencies.

Filing calendar you can copy

• PND 51 half year return Due two months after the end of the first six months of the accounting period. For calendar year taxpayers this is 31 August on paper or 8 September if e filed within the extension window.

• PND 50 annual return Due 150 days after year end, with 8 extra days if e filed before 31 January 2027. For a 31 December year end that is by 30 May on paper or the first week of June online.

FAQs

What is the standard Thailand corporate income tax 2025 rate The standard CIT rate is 20 percent. SMEs that meet thresholds use reduced bands of 0 percent, 15 percent, and 20 percent on slices of net profit.

How does the PND 51 estimate work You pay half of the estimated annual tax. If the estimate is more than 25 percent below actual full year net profit without reasonable cause, Section 67 ter imposes a 20 percent surcharge on the shortfall.

How long can I carry losses forward Five accounting periods from the loss year. No carryback.

Is there an online filing grace period Yes. The Revenue Department has extended the 8 day e filing grace period for specified returns through 31 January 2027.

What interest applies if I pay late A 1.5 percent per month surcharge generally applies to late paid tax, or 0.75 percent per month if an official payment extension is granted.

How GENTLE LAW IBL executes and de risks Thailand corporate income tax 2025

• CIT calendar and e filing We map PND 50 and PND 51 to your financial year and apply the 8 day extension where it lawfully applies.

• Computation quality We build a defensible tax pack aligned to Section 65 bis computation rules and Section 65 ter disallowances, with a loss continuity schedule.

• PND 51 control We run a mid year forecast and variance tracker to avoid Section 67 ter surcharges for underestimation.

• Pillar Two alignment For qualifying MNE groups we reconcile CIT and top up tax data across entities.

Call to action

If you want a clean, audit ready program for Thailand corporate income tax 2025, GENTLE LAW IBL can manage PND 50 and PND 51, build Section 65 bis and Section 65 ter computations, track loss carryforward, and align CIT with transfer pricing and Pillar Two where relevant.

Book a consultation: https://www.gentlelawibl.com