Tax Residency Rules by Country: Day Thresholds for Portugal, Thailand, Spain, Italy, and More

March 19, 20267 min read

Every country defines tax residency differently. Most use a day threshold, but the counting method, the exceptions, and the additional criteria vary. Portugal uses a rolling 12-month period. Thailand uses a calendar year with a 180-day threshold. Spain counts calendar year days but also considers your economic center. Knowing the threshold is not enough. You need to know exactly how each country counts.

This guide covers seven countries where Jetseen's users most commonly track days: Portugal, Thailand, Spain, Italy, Singapore, Canada, and Australia.

Quick summary: Most countries use a 183-day threshold, but Thailand uses 180 days. The counting period varies: calendar year (Spain, Italy, Thailand, Singapore, Canada), fiscal year (Australia July-June, UK April-April), or rolling 12-month period (Portugal, UAE). Partial days count as full days in most jurisdictions. Every country has additional criteria beyond day counting.

Portugal

Threshold: 183 days in any 12-month period starting or ending in the fiscal year.

Counting method: Rolling 12-month period (hybrid). Under Article 16 of the Portuguese tax code (CIRS), you are resident if present for 183 days "in any 12-month period starting or ending in the fiscal year concerned," according to PwC's Portugal tax summary. The fiscal year is the calendar year (January to December), but the 12-month window can extend beyond it. Days from late in one year combined with early days in the next can trigger residency.

Alternative test: You are also resident if you have a dwelling in Portugal on December 31 of the relevant year that suggests an intention to maintain it as your habitual residence.

Partial days: Count as full days.

Recent changes: The Non-Habitual Resident (NHR) regime was terminated for new applications effective March 2024. It was replaced by the IFICI (Tax Incentive for Scientific Research and Innovation) program, sometimes called NHR 2.0. The day-counting rules for standard tax residency have not changed.

Consult a professional if: You are relying on the IFICI regime, or if you have a property in Portugal but spend fewer than 183 days there. The "habitual residence" test is subjective.

Thailand

Threshold: 180 days (not 183).

Counting method: Calendar year (January 1 to December 31). Any part of a day counts as a full day. The 180 days do not need to be consecutive, according to PwC's Thailand tax summary.

Tax obligation: Since January 1, 2024, Thailand taxes foreign-sourced income remitted by tax residents, regardless of when it was earned. Previously, only income earned and remitted in the same year was taxed.

Practical impact: If you spend 180 days or more in Thailand and transfer money into a Thai bank account, that transfer may be subject to Thai personal income tax. This is a major change from the pre-2024 rules.

Consult a professional if: You are a tax resident remitting foreign income to Thailand. The rules changed significantly in 2024 and enforcement is still evolving.

Spain

Threshold: 183 days in a natural year (calendar year).

Counting method: Calendar year (January 1 to December 31). According to Spain's Agencia Tributaria, partial days count as full days. The 183 days do not need to be consecutive.

Important detail: Temporary absences from Spain count as days of presence unless you can prove tax residency in another country. If you leave Spain for a week but cannot document that you are a tax resident elsewhere, those 7 days still count toward your Spanish total.

Alternative test: Spain also considers you a tax resident if the center of your economic interests is in Spain, or if your spouse and dependent minor children live in Spain (unless you prove otherwise). You can be claimed as a Spanish tax resident with fewer than 183 days if these factors apply.

Consult a professional if: Your family lives in Spain but you work elsewhere, or if your primary business income originates in Spain.

Italy

Threshold: 183 days in a calendar year.

Counting method: Calendar year (January 1 to December 31). The 183 days do not need to be consecutive. Partial days count as full days, confirmed by the Italian Revenue Agency's Circular No. 20/E issued in November 2024.

Alternative tests: Italy also considers civil registry enrollment (anagrafe), domicile (center of personal and family relations), and habitual abode. Being enrolled in the Italian civil registry creates a presumption of residence regardless of days spent.

Recent changes: Italian tax residency rules were updated effective January 1, 2024, expanding the definition to include anyone who has their "domicile" in Italy, defined as the place of the person's principal personal and family relationships.

Consult a professional if: You have Italian property, family in Italy, or are enrolled in the anagrafe even while living abroad.

Singapore

Threshold: 183 days in a calendar year.

Counting method: Calendar year (January 1 to December 31). Physical presence for 183 or more days makes you a Singapore tax resident for that Year of Assessment, according to the Inland Revenue Authority of Singapore (IRAS).

Key detail: Singapore taxes on a territorial basis. Even as a tax resident, you are generally only taxed on income earned in or remitted to Singapore. Foreign-sourced income received in Singapore by resident individuals is usually exempt, with some exceptions.

Consult a professional if: You receive foreign-sourced income in Singapore or if you split time between Singapore and another country that also claims you as a tax resident.

Canada

Threshold: 183 days in a calendar year (sojourner rule).

Counting method: Calendar year (January 1 to December 31). Under the "sojourner rule," you are deemed a Canadian tax resident if you sojourn (stay) in Canada for 183 or more days in a calendar year, according to the Canada Revenue Agency.

Alternative tests: Canada also uses "significant residential ties" (home, spouse/partner, dependents in Canada) and "secondary ties" (bank accounts, driver's license, health insurance). You can be a Canadian tax resident with fewer than 183 days if you maintain significant ties.

Key difference from other countries: Canada taxes residents on worldwide income. If you trigger residency through the sojourner rule, you owe tax on all income from all sources, not just Canadian income.

Consult a professional if: You left Canada but maintain a home, bank accounts, or family ties there. The CRA may consider you a continuing resident despite being abroad.

Australia

Threshold: 183 days in the income year.

Counting method: Fiscal year (July 1 to June 30). The 183 days do not need to be consecutive, according to the Australian Taxation Office (ATO).

Important caveat: Spending 183 days does not automatically make you a tax resident. The ATO states that the 183-day test does not apply if your "usual place of abode" is overseas and you have no intention to take up residency in Australia. This is a facts-and-circumstances determination.

Other residency tests: Australia uses multiple tests: the "resides" test (primary, based on overall circumstances), the domicile test, the 183-day test, and the Commonwealth superannuation test. The 183-day test is just one of four.

Consult a professional if: You spend 183 days in Australia but maintain your primary home and life elsewhere. The ATO applies a broader analysis than just day counting.

How to track days across multiple countries

If you split time between three or four of these countries, you are running different counting methods simultaneously. Portugal's rolling 12-month window. Spain's calendar year with the "absences count" rule. Australia's July-to-June fiscal year.

I built Jetseen with 12 country-specific rule engines for exactly this reason. Each engine applies the correct counting method, period, and threshold for its jurisdiction. You enter your trips once and see where you stand against every rule that applies to you.

Whatever tool you use, make sure it handles the specific counting method for each country. A simple "total days per country per year" spreadsheet does not account for rolling windows, fiscal year boundaries, or weighted formulas.

FAQ

Is the 183-day rule the same everywhere? No. Thailand uses 180 days. The counting period varies: calendar year, fiscal year, or rolling 12-month period. And many countries can claim you as a resident with fewer days based on ties, property, or economic interests.

Do partial days count? In most countries, yes. Spain, Italy, Thailand, and the UAE all count any part of a day as a full day. Land at 11pm and that counts. The UK is an exception: it uses the midnight rule (you must be present at midnight for the day to count).

Which countries use rolling windows instead of calendar years? The Schengen Area (90/180), UAE (183 days in 12 months), and Portugal (183 days in any 12-month period overlapping the fiscal year). Most other countries use calendar or fiscal years.

Can I be tax resident in a country even under 183 days? Yes. Spain considers your economic center and family. Italy considers civil registry enrollment. Canada considers residential ties. Australia uses a multi-factor "resides" test. Day counting is one factor, not the only one.