About My Thai Taxes

What is My Thai Taxes?

My Thai Taxes is a free online calculator and information resource designed to help individuals understand and estimate their Thai personal income tax obligations. Whether you are a salaried employee, freelancer, sole proprietor, or company director, the tools here are built to walk you through Thailand's tax system in plain language — without requiring an accounting background.

Why we built it

Thailand's personal income tax rules can be confusing, especially for expats and digital nomads navigating the 180-day residency rule, foreign income remittance requirements, and the range of allowances available to reduce taxable income. Good information exists, but it's scattered across Revenue Department PDFs, accounting-firm blog posts, and forum threads that often disagree with each other — and most calculators online don't show their work. My Thai Taxes was built to bring that into one place: a calculator that shows every step of the math, and plain-language guides that explain the reasoning behind it, so you can understand your own tax position rather than just trusting a number.

How the calculations work

The annual tax calculator follows the same structure the Revenue Department uses for a PND90/91 return: it takes your income by type, applies the relevant flat-rate or actual-expense deduction, subtracts your allowances (personal, spouse, children, parents, insurance, retirement funds, donations, and so on), and runs the resulting taxable income through Thailand's progressive tax brackets (0% to 35%). The monthly withholding estimator uses the same underlying logic to check whether the right amount of tax is being deducted from a salary each month. Every step is shown in the results, not hidden behind a single output number — you can see exactly which deduction, allowance, or bracket produced your result.

How information is sourced

Every tax rule, rate, and threshold used in the calculator is tracked in a public sources registry — the Thai Tax Rules Registry in this site's open-source repository. For each figure, the registry records where it came from (ideally a primary Thai Revenue Department document, otherwise reputable secondary sources such as major accounting firms or Thai law firms), what conditions or limitations apply, and whether that figure has been independently verified. Where a value could not be confirmed against a primary source, or where sources disagree, that is flagged openly rather than presented as settled fact. This is a deliberate choice: we'd rather show you where our confidence is lower than quietly guess.

Who maintains the site

My Thai Taxes is built and maintained independently by a single developer. It is not run by a law firm, accounting firm, or the Thai government, and nothing on this site should be taken as advice from a licensed tax professional — see the disclaimer below. The site is a personal project aimed at making Thai tax information more transparent and accessible.

How often information is reviewed

Tax rules and figures are reviewed periodically, and whenever a change to Thai tax law is identified. Each figure in the calculator is tracked in the sources registry above along with its source and verification status, so outdated or disputed values can be caught and corrected rather than sitting unnoticed. If you spot something that looks wrong or out of date, please let us know — see Contact below.

What the site offers

→Annual Tax Calculator — A step-by-step calculator covering income, deductions, allowances, withholding, and a full tax breakdown — with a downloadable PDF filing reference at the end.
→Monthly Withholding Estimator — A quick tool to check whether the correct amount of tax is being deducted from your monthly salary.
→Articles — In-depth guides on Thai tax topics including residency rules, freelancer obligations, double tax agreements, retirement income, and more.
→FAQ — Answers to the most common questions from expats, digital nomads, and Thai residents about filing, deductions, and staying compliant.

For developers & AI agents

The annual tax calculation is also available as a free, open API — useful for embedding a Thai tax estimate elsewhere, or for AI agents that need to compute a live number rather than guess one. No API key or account required.

MCP endpoint (Streamable HTTP, tool name calculate_thai_annual_income_tax):

https://mythaitaxes-mcp.hannwill999.workers.dev/mcp

REST endpoint (plain POST JSON, same calculation):

curl -X POST https://mythaitaxes-mcp.hannwill999.workers.dev/api/calculate-annual-tax \
  -H "Content-Type: application/json" \
  -d '{"annualIncome": 800000, "maritalStatus": "married"}'

Covers salaried-employee income tax for now. Results are estimates — see the disclaimer below.

Disclaimer

The calculators and articles on this site are for informational and estimation purposes only. They do not constitute professional tax advice and should not be relied upon as a substitute for guidance from a qualified Thai tax advisor or accountant. Tax rules can change — always verify current regulations with the Thai Revenue Department or a licensed professional before filing.

Contact

For questions, feedback, or corrections, reach out at info@mythaitaxes.com. If you spot an error in any article or calculator, please get in touch — accuracy matters and updates are made as Thai tax rules change.