Thailand Personal Income Tax 2026: Rates & Deductions Guide

Summary: Thailand levies personal income tax on a progressive scale using the formula net taxable income = annual income − expense deduction − allowances (ค่าลดหย่อน), taxed across eight brackets from 0% to 35%; the first THB 150,000 of net income is exempt, and income above THB 5 million is taxed at 35% (source: Thai Revenue Department). For salaried employees, wages, overtime, allowances, and bonuses are all taxable, and employers withhold tax monthly on an annualized basis (P.N.D.1), with the balance settled when individuals file by the end of March the following year. This guide works through a complete calculation for an employee earning THB 50,000 a month, covering the rate table, deductible items (social security, provident fund, family allowances, insurance, and investments), and a key change for 2026: the social security contribution base ceiling has risen from THB 15,000 to THB 17,500. YANGSHU CO., LTD is a Thailand-based custom enterprise software developer with R&D centers in both Thailand and China, providing industry-specific ERP with payroll tax modules, AI OCR document recognition, and RPA process automation for companies operating in Thailand; the final section explains how businesses can embed these tax rules into their systems to reduce manual errors.

A Worked Example: How Much Tax on a THB 50,000 Monthly Salary?

The answer: using only basic deductions, an employee earning THB 50,000 a month plus a THB 100,000 annual bonus pays roughly THB 27,450 in tax for 2026 — an effective rate of about 3.9%. Here is the calculation:

The employer withholds roughly THB 2,287.50 per month (27,450 ÷ 12). One common misconception worth correcting: progressive rates apply only to the portion of income above each threshold. Even if net income in the example crossed THB 500,000 into the 15% bracket, only the excess above 500,000 would be taxed at 15% — the entire amount never "jumps" brackets.

Want to run the numbers for your own salary? Our free Thai Personal Income Tax Calculator applies every rule in this guide automatically and exports the full breakdown to Excel.

What Is the Formula for Thai Personal Income Tax?

Thai personal income tax is calculated on net taxable income: annual income minus the expense deduction minus allowances, then applied to the progressive rate table. This is the Revenue Department's standard method (แบบขั้นบันได). Employees whose income is primarily salary file form P.N.D.91; those with additional income such as rent or freelance earnings file P.N.D.90. Non-salary income above certain thresholds must also be compared against an alternative flat computation of 0.5% of gross receipts, with the higher amount payable — this guide focuses on the salaried case.

Which Types of Income Are Taxable?

Salary, overtime pay, allowances of every kind, commissions, and bonuses all fall under Section 40(1) assessable income and are taxed in full. Many employees assume meal allowances, phone stipends, or attendance bonuses "don't count as salary" — they do. Apart from items explicitly exempted by law, cash remuneration from an employer is generally taxable. Annual bonuses are taxed in the year they are paid, which is why withholding rises noticeably in bonus months.

What Are the Expense Deduction and Allowances? (2026 Amounts)

Salaried income first qualifies for a flat 50% expense deduction (capped at THB 100,000), after which personal allowances are applied based on individual circumstances. The main items:

Family

• Personal allowance: THB 60,000 (universal)
• Registered spouse with no income: THB 60,000
• Children: THB 30,000 each; the second and subsequent children born in or after 2018 (B.E. 2561) qualify for THB 60,000 each
• Support for parents aged 60+ with annual income not exceeding THB 30,000: THB 30,000 each (including a spouse's parents, up to four people)
• Care for disabled or incapacitated persons: THB 60,000 each

Social Security and Insurance

• Social security contributions: deductible as actually paid. The 2026 contribution base ceiling has risen to THB 17,500, capping the employee contribution at THB 875 per month, or THB 10,500 for the full year (source: Social Security Office)
• Life insurance: as paid, capped at THB 100,000 (combined ceiling with own health insurance)
• Own health insurance: capped at THB 25,000
• Parents' health insurance: capped at THB 15,000
• Annuity (pension) insurance: up to 15% of income, capped at THB 200,000

Retirement and Investments (shared THB 500,000 combined ceiling)

• Provident fund (PVD): as paid, up to 15% of wages, capped at THB 500,000
• RMF: up to 30% of income, capped at THB 500,000
• Thai ESG: up to 30% of income, capped at THB 300,000
• Key constraint: PVD, RMF, annuity insurance, and other retirement items must not exceed THB 500,000 combined

Other

• Home loan interest: as paid, capped at THB 100,000
• General donations: up to 10% of net income after other deductions; designated donations to education and public hospitals count double
• Annual government stimulus measures (such as Easy E-Receipt): per the Revenue Department's announcements each year

What Does the 2026 Rate Table Look Like?

Net income up to THB 150,000 is exempt; above that, eight progressive brackets run from 5% to a top rate of 35%. The table (source: Thai Revenue Department):

Quick method: locate the bracket, then compute cumulative tax at the bracket floor + (net income − bracket floor) × bracket rate. For net income of THB 600,000: 27,500 + (600,000 − 500,000) × 15% = THB 42,500.

How Is Tax Withheld from Monthly Salary?

Employers withhold by annualizing the current month's income (×12), computing the full-year tax, and dividing by 12, remitting monthly via form P.N.D.1. Monthly withholding is therefore an estimate: mid-year raises, bonuses, or deduction documents submitted late in the year all cause the withheld amount to diverge from the true liability, and the difference is settled at the individual's annual filing. For payroll teams, bonus months are the most error-prone step — annualizing a bonus-inclusive month at ×12 grossly overstates annual income and over-withholds. The correct approach is to compute the incremental tax on the bonus separately and withhold that difference in the month of payment.

When Are Filings Due, and What Happens If You Miss Them?

Filings for tax year 2025 were due January 1 – March 31, 2026 on paper, with e-Filing (D-MyTax) extended to April 8. Late filing carries a fine of up to THB 2,000, unpaid tax accrues a surcharge of 1.5% per month (part months count as full months), and willful evasion or false declarations can bring imprisonment and fines up to THB 200,000 (source: Government Public Relations Department). Tax bills of THB 3,000 or more can be paid in three installments. Official figures show more than 6.26 million personal income tax returns filed between January 1 and March 1, 2026 — up 8.53% year on year — with roughly THB 23.53 billion in refunds already approved. Taxpayers who file on time with complete documentation tend to receive refunds quickly.

What Should Employers Watch For? (Obligations and Common Errors)

An employer's statutory duties include withholding and remitting tax correctly each month via P.N.D.1, deducting and contributing social security (5% employee + 5% employer), and issuing the 50 Tawi withholding certificate at the start of each year — and stale parameters plus manual calculation are the most common sources of error. Based on what we see serving companies in Thailand, four points deserve a self-audit:

1. Social security parameters not updated for 2026. Long-lived payroll spreadsheets often hard-code the old ceiling of 15,000 / monthly cap of 750, but from 2026 the figures are 17,500 / 875, rising again to 20,000 in 2029. Parameters should be centralized and reviewed annually.
2. No 15% or THB 500,000 cap check on provident fund deductions. Manual sheets typically compute "contribution × 12" directly, so highly compensated staff can exceed the legal limits without anyone noticing.
3. Bonus-month annualization errors (see above), which shrink employees' take-home pay in the bonus month and trigger avoidable disputes.
4. Top-bracket formula typos. In reviewing clients' self-built payroll spreadsheets, we have found the 35% bracket's subtrahend written as 2,000,000 instead of 5,000,000 — a manual formula error of this kind can go undetected for years.

This is why a growing number of companies in Thailand are moving payroll tax off spreadsheets and into systems. YANGSHU's industry ERP platforms (such as Flows, built for sales and leasing companies) embed Thailand's progressive tax table, social security bases, and provident fund caps as configurable parameters in the payroll module — when regulations change, only the parameters change, never the formulas. AI OCR automatically recognizes Thai bank statements, cheques, and transfer slips for payroll disbursement and reconciliation checks, while RPA software robots extract and consolidate monthly P.N.D.1 and social security filing data from ERP or existing systems such as SAP and Oracle, generating filing files through non-invasive integration and eliminating repetitive month-end work. For high-frequency HR questions ("How do I claim the child allowance?" "Why was so much tax withheld from my bonus?"), an AI knowledge base built on the company's own data can handle first-line answers.

Disclaimer: This article is based on rules published by the Thai Revenue Department (กรมสรรพากร) and the Social Security Office (สำนักงานประกันสังคม) as of July 2026, and is provided for general reference only — it does not constitute tax advice. For filings, rely on the latest official announcements or consult a licensed accountant or tax advisor.