ไทย
English
PND.1 is the monthly withholding tax filing for personal income tax that Thai employers deduct from employee salaries. The calculation projects the employee’s annual income, subtracts allowable deductions, applies Thailand’s 2026 progressive tax brackets, then divides by 12 to determine the monthly withholding. Employers must submit PND.1 by the 7th of the following month (or the 15th via e-filing) — late submissions trigger fines and monthly interest charges.
Picture this familiar end-of-month conversation in a Bangkok HR office: an employee calls in confused — “Why is my tax higher this month than last?” Or worse, the Revenue Department issues a retroactive assessment because last year’s deductions were undercounted. Both scenarios are common in companies that run payroll manually with outdated tax formulas. This guide walks you through PND.1 calculation under Thailand’s current tax law, with a worked example you can apply to your team’s payroll immediately.
💡 What is PND.1?
PND.1 (P.N.D.1) is the “Personal Income Tax Withholding Return,” filed under Section 59 of the Thai Revenue Code. Employers must file PND.1 every month with the Revenue Department, reporting employee salaries and the tax withheld. The annual summary form is PND.1 Kor, due by February 28 of the following year.
Why HR Must Calculate PND.1 Correctly from Day One
A miscalculated PND.1 hurts both sides — employees may overpay (losing cash flow) or underpay (facing a retroactive bill plus penalties at year-end). For the company, a Revenue Department audit can result in fines and a loss of trust with employees. Multinational employers in Thailand frequently underestimate this risk because corporate global payroll teams may not be familiar with Thai-specific deduction rules.
Numbers HR teams in Thailand should know:
- 64% of HR teams in mid-sized organizations (50–500 employees) still calculate payroll tax manually — Mercer Total Workforce Management Thailand 2024
- The Revenue Department found payroll errors in 38% of HR audits in 2023 — Thai Revenue Department Annual Report
- Late PND.1 fines: 100 THB per form for the first 7 days late, 200 THB per form after that, plus 1.5% monthly interest on the unpaid tax
The most common errors come from not updating an employee’s deduction profile (marriage, new children, starting an LTF/SSF investment) or not adjusting for new Revenue Department announcements. HR teams need a documented annual review process plus a clear update channel whenever an employee’s personal status changes.
PND.1 Structure and 2026 Tax Brackets
PND.1 uses Thailand’s progressive personal income tax brackets, published by the Revenue Department and effective in 2026. HR should verify the current rates at the start of every January before running the year’s first payroll.
2026 Personal Income Tax Brackets:
| Annual Net Income (THB) | Rate | Cumulative Tax at Top of Band |
|---|---|---|
| 0 – 150,000 | Exempt | 0 |
| 150,001 – 300,000 | 5% | 7,500 |
| 300,001 – 500,000 | 10% | 27,500 |
| 500,001 – 750,000 | 15% | 65,000 |
| 750,001 – 1,000,000 | 20% | 115,000 |
| 1,000,001 – 2,000,000 | 25% | 365,000 |
| 2,000,001 – 5,000,000 | 30% | 1,265,000 |
| Over 5,000,000 | 35% | — |
Core deductions HR must collect from each employee:
- Personal allowance: 60,000 THB per person
- Spouse with no income: 60,000 THB
- Legal children: 30,000 THB per child (60,000 THB for the second child onward if born after 2018)
- Dependent parents: 30,000 THB per parent (both must be 60+ years old, income under 30,000/year)
- Social Security: actual amount, max 9,000 THB
- Provident Fund (PVD): up to 15% of income, max 500,000 THB
- Life insurance: actual amount, max 100,000 THB
- LTF/SSF: up to 30% of income, max 200,000 THB
Additional deductions (e-Donation, home loan interest, etc.) have their own caps. HR should distribute the official deduction declaration form (Lor Yor 01) to all employees at the start of every year and update records whenever personal status changes.
The 5-Step Monthly PND.1 Calculation
PND.1 calculation follows the same formula as annual personal income tax — just divided by 12 to find the monthly amount. HR teams managing multiple employees can apply this 5-step sequence uniformly across the payroll.
Step 1 — Project annual income
Multiply the monthly salary by 12 and add any expected extras (bonus, commission, allowance). HR should keep the estimate reasonable. For employees who joined mid-year, prorate based on the actual working months in that calendar year.
Step 2 — Apply the personal expense allowance
Under Section 42 Bis of the Revenue Code, employees deduct 50% capped at 100,000 THB. Anyone earning over 200,000 THB per year hits the 100,000 cap immediately.
Step 3 — Apply personal deductions
Pull data from each employee’s Lor Yor 01 declaration form. Sum all eligible deductions (personal, spouse, children, Social Security, Provident Fund, life insurance, LTF/SSF, etc.). The result is “net taxable income.”
Step 4 — Apply the progressive brackets
Run the net taxable income through the 2026 progressive table above. Calculate band by band (not a single rate on the full amount), then sum to get the annual tax.
Step 5 — Determine the monthly withholding and file PND.1
Divide annual tax by 12 — that’s the amount withheld each month. Enter this figure on the PND.1 form alongside the employee’s details (tax ID, full name, income), then file via e-filing at rd.go.th by the 15th of the following month.
If an employee earns an unexpected one-off (such as a mid-year bonus), HR must recalculate the annual tax including the bonus, subtract the tax already withheld, and add the difference to that month’s withholding.
Worked Example: PND.1 for One Employee
Take a realistic Thai employee profile — let’s call her Por, salary 45,000 THB, single, no children, paying 750 THB monthly to Social Security and 5% (2,250 THB monthly) to the Provident Fund. No other deductions.
Calculation steps:
- Projected annual income: 45,000 × 12 = 540,000 THB
- Deduct personal expense allowance: 50% capped at 100,000 THB → 100,000 THB → remaining 440,000 THB
- Apply personal deductions: Personal 60,000 + Social Security 9,000 (750×12) + Provident Fund 27,000 (2,250×12) = 96,000 THB → Net taxable income 344,000 THB
- Apply progressive brackets: 0–150,000 = exempt / 150,001–300,000 = 150,000 × 5% = 7,500 / 300,001–344,000 = 44,000 × 10% = 4,400 → Total annual tax 11,900 THB
- Monthly withholding: 11,900 ÷ 12 = 991.67 THB withheld and reported on PND.1 every month.
When an employee receives a one-off bonus or commission in a specific month, HR must recalculate (project new annual income including the bonus, calculate new annual tax, subtract tax already withheld) — the difference is that month’s tax. This step is complex and is where manual calculations frequently break.
Reducing Admin Work with Pinno Payroll Automation
For organizations with 50+ employees or complex salary structures (multiple roles, OT, multiple allowance types), calculating PND.1 manually becomes both a time sink and an audit risk. Pinno Payroll Automation calculates PND.1 every month, updates tax brackets as the Revenue Department publishes them, and generates the e-filing file ready for direct submission.
The system also integrates with Employee Self-Service, letting employees update their own deduction information at any time (marriage, new child) — the next month’s tax calculation reflects the change immediately, without HR needing to re-enter anything. It also connects to Time Management, which feeds OT data directly into payroll.
About Pinno
Pinno is a Thailand-built HR Cloud Software developed by Pinno Solutions Co., Ltd. under the PRTR Group — a leading HR solutions provider in Thailand for more than 30 years. Today over 20,000 organizations trust Pinno across Payroll, Time, Benefits, Performance, and Employee Self-Service in a single platform. Website: https://pinno.io
Frequently Asked Questions (FAQ)
Q: How early can PND.1 be filed through e-filing?
A: The Revenue Department’s e-filing portal at rd.go.th allows filing by the 15th of the following month (extended from the 7-day window for paper filing). We recommend filing no later than the 10th to leave buffer time if the portal has technical issues. If an employee has zero tax due, PND.1 must still be filed showing “0 THB” — not filing is treated as non-compliance.
Q: If an employee joins mid-month, how do we calculate their tax?
A: Use the actual first-month salary (prorated by working days) for that month’s PND.1. From the next month, use the full salary. For the annual income projection, multiply the full monthly salary by the remaining calendar months plus the prorated first-month amount.
Q: Do employees earning under 25,833 THB/month still need PND.1 filing?
A: Yes, but their tax will be 0 THB. Their projected annual net income (after the personal expense allowance and personal deduction) falls below the 150,000 THB threshold where tax begins. The employer must still file PND.1 with the 0 THB tax line. Not filing is non-compliance and triggers fines.
Q: What’s new in 2026 deductions?
A: HR must check rd.go.th at the start of every year. The government periodically announces stimulus measures that add or modify deductions (such as Easy E-Receipt or Shop Dee Mee Khuen). These often have limited time windows. HR should communicate any updates to employees through email or the HR portal as soon as they’re announced.
Q: If HR miscalculates and the employee gets a retroactive bill at year-end, is the company liable?
A: Under Section 50 of the Revenue Code, the employer is responsible for accurate withholding. If the Revenue Department reassesses, the employer is jointly liable for the unwithheld tax plus interest. An HR system with an audit log is one of the strongest defenses against this kind of liability.
Run accurate payroll while cutting HR admin time by 70% — Book a free demo to see Pinno Payroll Automation calculate PND.1 every month and submit through e-filing in a single platform.
Let Pinno Take Care of Your HR
HR Cloud Software trusted by 20,000+ organizations in Thailand
