Running payroll in Thailand looks deceptively simple until the first PND.1 lands a day late and the Revenue Department slaps a THB 200 fine plus a 1.5%-per-month surcharge on top of unpaid tax (VB & Partners). For foreign-owned companies, the trip-ups stack up fast: forms are in Thai, deadlines shift on every Buddhist holiday, expat fringe benefits get misclassified, and the Social Security ceiling just changed on 1 January 2026 (HLB Thailand). Miss one filing and you are not just paying a fine — for BOI-promoted companies, an unfiled PND.1 can block work permit renewals for every foreign employee on the payroll (Lexology).
This is the 2026 calendar, every form, every rate, every penalty.
The Filings — At-a-Glance Monthly Calendar
| Form | What it is | Paper | E-filing | Who files |
|---|---|---|---|---|
| PND.1 | Withholding on salaries | 7th of next month | 15th | All employers |
| PND.2 | Withholding on dividends, interest, royalties to individuals | 7th | 15th | Companies paying individuals |
| PND.3 | Withholding on payments to individuals (services, rent) | 7th | 15th | Any business |
| PND.53 | Withholding on payments to Thai companies | 7th | 15th | Any business |
| PND.54 | Withholding on payments to foreign companies | 7th | 15th | Any business paying overseas |
| PP.30 | VAT return (mandatory even at zero revenue) | 15th | 23rd | VAT-registered |
| SSO 1-10 | Social Security contributions | 15th | 15th | All employers |
| PND.51 | Half-year corporate tax | 31 Aug (calendar year) | — | All companies |
| PND.50 | Annual corporate tax | 31 May (calendar year) | — | All companies |
The e-filing extension was renewed and runs through 31 January 2027 (Forvis Mazars).
Personal Income Tax Withholding (PND.1) — Rates, Brackets, Foreign Employee Edge Cases
Employers withhold PIT each month using Thailand's 8-bracket progressive table (PwC Worldwide Tax Summaries):
| Net annual income (THB) | Rate |
|---|---|
| 0 — 150,000 | Exempt |
| 150,001 — 300,000 | 5% |
| 300,001 — 500,000 | 10% |
| 500,001 — 750,000 | 15% |
| 750,001 — 1,000,000 | 20% |
| 1,000,001 — 2,000,000 | 25% |
| 2,000,001 — 5,000,000 | 30% |
| Over 5,000,000 | 35% |
The standard employment deduction is 50% of income, capped at THB 100,000.
Foreign employee edge cases that catch founders out:
- 180-day residency rule. Anyone in Thailand 180+ days in a calendar year is a tax resident and taxable on Thai-sourced income plus foreign income remitted into Thailand.
- BOI minimum salary thresholds. Under BOI Announcement Por. 8/2568, foreign hires under BOI promotion must be paid from Thai payroll and substantiated by PND.1 filings — shadow payroll or offshore-only structures fail the audit (RBA Group).
- Fringe benefits are taxable. Housing allowance, school fees, home-leave airfare, tax equalization — all assessable income unless specifically exempt. These are the line items that get missed.
Social Security Contributions — 5% Each Side, New THB 875 Monthly Cap
Effective 1 January 2026, the wage ceiling for Section 33 contributions jumped from THB 15,000 to THB 17,500. The rate is unchanged at 5% employer + 5% employee, but the maximum monthly contribution per person rose from THB 750 to THB 875 each side (HLB Thailand, Acclime).
Phased rollout: ceiling rises again in 2029 and reaches THB 23,000 by 2032.
Form SSO 1-10 is due to the Social Security Office by the 15th of the following month. Foreign staff on work permits must be registered in the SSF — there is no expat carve-out.
Withholding on Vendor Payments (PND.3 / PND.53 / PND.54)
| Form | Recipient | Common rates |
|---|---|---|
| PND.3 | Thai individuals (freelancers, landlords) | 1—5% services, 5% rent, 3% professional fees |
| PND.53 | Thai companies | 1% transport, 2% advertising, 3% services/professional, 5% rent |
| PND.54 | Foreign companies (no Thai PE) | 15% services/royalties/interest, 10% dividends, 10% branch profit remittance |
PND.54 is the one foreign-owned companies miss most — every payment to an overseas software vendor, parent-company management fee, or offshore consultant triggers it (Forvis Mazars, Sherrings). Check the relevant Double Tax Agreement before withholding the full 15% — most DTAs reduce royalty and service rates to 5—10%.
VAT (PP.30) — Monthly Filing Even at Zero Revenue
Every VAT-registered company files PP.30 monthly regardless of whether it invoiced a single baht. Paper filing is due by the 15th; e-filing by the 23rd. Six consecutive months of non-filing and the Revenue Department deregisters your VAT number — forcing a fresh Por.Por.01 application (Forvis Mazars).
A new PP.30 form and attachment take effect 1 March 2026 (Forvis Mazars) — update your accounting software before the February close.
Half-Year and Year-End Corporate Filings (PND.51, PND.50)
- PND.51 (half-year): estimated tax on projected full-year profit, half paid up front, due within 2 months after the end of the first 6 months. For a calendar-year company, that is 31 August 2026 (Sherrings).
- PND.50 (annual): full corporate income tax return due within 150 days of fiscal year-end. Calendar-year companies file by 30 May 2026 for FY2025 (150 days from 31 December 2025).
Under-estimating PND.51 net profit by more than 25% without reasonable grounds triggers a 20% surcharge on the shortfall — the single biggest avoidable cost on the corporate side.
Common Mistakes for Foreign-Owned Companies
- Late SSO. The 15th deadline overlaps PP.30 paper-filing day, and finance teams prioritize tax over SSO. Late SSO triggers 2% per month surcharge plus contribution arrears.
- Wrong PND form. Paying a sole proprietor on PND.53 instead of PND.3 (or vice versa) means the recipient cannot claim the withholding certificate, which often surfaces only when they complain months later — and you have to refile.
- Undeclared expat fringe benefits. Housing, tuition, and tax equalization are assessable income for PND.1 purposes. Missing them inflates net pay on paper and triggers reassessment on audit.
- Foreign-currency conversion timing. Withholding on USD or EUR invoices must use the Bank of Thailand reference rate on the date of payment, not the invoice date. Using the wrong date is a quiet but routine audit finding.
- Forgetting PND.54 on SaaS subscriptions. Slack, Notion, AWS, Figma — every one is a foreign service payment. 15% withholding applies unless the DTA reduces it and you can produce the vendor's residency certificate.
- Missing BOI ratio filings. From 1 January 2026, BOI manufacturing companies with more than 100 employees and promotion certificates issued before 5 June 2025 must meet the new 70:30 Thai-to-foreign ratio rules or the BOI system blocks work permit renewals (service-sector and smaller manufacturers are not bound by the new ratio) (Lexology).
End-to-end payroll, handed off
Thailand payroll is not hard, but it is unforgiving — one missed PND.1 cascades into surcharges, blocked work permits, and a six-month VAT re-registration nightmare. Motherducker's Operation Services runs end-to-end payroll for foreign-owned Thai entities: PND.1, PND.3/53/54, PP.30, SSO, BOI compliance, and the half-year and annual corporate filings, all on a single monthly cadence.