Personal Income Tax in Thailand.

Who pays personal income tax in Thailand

Personal income tax in Thailand turns on one question first: are you a tax resident? The Revenue Department treats anyone who spends more than 180 days in Thailand in a calendar year as a resident for tax purposes. A resident pays Thai tax on income earned in Thailand and on the portion of foreign-sourced income brought into the country. A non-resident pays Thai tax only on income from Thai sources.

The filing thresholds are low. A single person files once total income passes 60,000 baht in the tax year; a married couple files once combined income passes 120,000 baht. Crossing the threshold means a return is due even when no tax ends up payable.

That framework is simple to state and messy to apply, which is why much of the work of tax lawyers in Thailand and tax advisory firms is exactly this: confirming residency, classifying income, and getting the return right the first time.

Tax in Thailand for expats

For a foreigner living in Thailand, three points do most of the work. First, the 180-day rule counts days of presence, not visa type: a retiree, a remote worker, and a posted employee are all residents once they cross it. Second, residency pulls remitted foreign income into scope, so the money you bring in matters, not just what you earn locally. Third, Thailand has a network of double tax agreements, and treaty relief can change what is taxable and where; applying it correctly is its own piece of work, covered on our tax treaty applications page.

Employment income is usually taxed before it reaches you: the employer deducts tax at source each month and the amounts are credited against your final liability when you file. The same crediting logic applies to tax withheld on other income types, which the withholding tax page covers from the payer's side.

An adviser earns their fee here by looking at the whole year: your days in the country, what you remitted and when, which treaty applies, and what the withholding certificates already cover. For many expats the outcome of that review is a refund position rather than a bill.

Filing: PND90, PND91, and the deadlines

The annual return is due by the last day of March following the tax year. The Revenue Department publishes two forms: PND91 for taxpayers whose income came from employment only, and PND90 for everyone else, including anyone with rental, freelance, investment, or mixed income. Filing electronically through the department's system carries an automatic eight-day extension of the deadline.

If the return shows tax overpaid, the refund is requested on the return itself and paid out through PromptPay. If it shows tax payable and the payment misses the deadline, a surcharge of 1.5% per month runs on the unpaid amount. When withholding has left you overpaid, the claim side of that is its own process, covered on the tax refund claims page.

What a tax firm does, and when it is worth paying for

A salaried employee with one Thai employer and no other income often files without help. The value of an adviser rises with each complication: foreign income and remittances, more than one income type, a year split between countries, equity compensation, or a treaty position worth documenting. Fees vary by firm and by how much of that applies to you, which is where comparing firms pays off.

Beyond the annual return, the same firms handle the forward-looking side: structuring the year ahead so residency, remittances, and reliefs work together rather than by accident. That work is covered on our tax planning page.

This page is general information, not legal advice. Rates, thresholds, and procedures change; for your own situation, speak with a qualified professional.