If you can work from anywhere, where do you actually pay tax?
It sounds simple. However, for remote employees and the startups that hire them, tax residency can mean either smooth compliance or an unexpected bill.
In a remote-first world, location is flexible. Tax rules are not.
The 183-Day Rule Is Only The Starting Point
Many countries begin with a basic test. If you spend 183 days or more in a country during a tax year, then you are often treated as a tax resident there.
The United States applies a version of this through the Substantial Presence Test. According to the IRS, the formula can count days from the prior two years using a weighted approach.
Think of it like a loyalty card. If you show up often enough, the system assumes you belong.
However, the 183-day rule is neither universal nor decisive on its own. Some countries add extra conditions. Others look beyond time and into ties. Therefore, counting days is step one, not the finish line.
Center Of Vital Interests And Real Life Ties
What if you split your year between two countries and hit 183 days in neither?
Then tax authorities often examine your “center of vital interests.” In plain terms, where is your real life based? Where does your family live? Where are your economic and personal connections strongest?
The 2026 edition of EY’s Worldwide Personal Tax and Immigration Guide explains that many jurisdictions use both day-count tests and a center-of-vital-interests analysis to determine residency.
Picture your life as a backpack. You may travel widely; however, the essentials stay in one place. If most of your relationships, assets, and routines sit in one country, then that country may claim you as a resident.
Tax residency is not only about physical presence but also about personal and economic gravity.
Treaty Tie Breakers When Two Countries Claim You
Sometimes two countries will both say you are a resident.
If a tax treaty exists, then tie-breaker rules apply. Under the OECD Model Tax Convention, the analysis generally looks at permanent home first, then center of vital interests, then habitual abode, and finally nationality.
In November 2025, the OECD updated its Model Tax Convention to clarify how cross-border remote work interacts with permanent establishment and treaty concepts. The update also addresses when remote work may create taxable presence for businesses.
If you have a permanent home in one country but not the other, then the outcome may be clear. If you have homes in both, then the facts matter more.
It is either straightforward or layered. There is rarely a casual middle ground.
U.S. Citizens Abroad And The Bona Fide Residence Test
Here is where things become uniquely American.
U.S. citizens are taxed on worldwide income, whether they live in Boston or Barcelona. However, they may qualify for the Foreign Earned Income Exclusion if they meet either the physical presence test or the bona fide residence test.
If you choose the residency route, then you must meet specific qualifying criteria for bonafide residence. In everyday terms, you must show that you have genuinely settled abroad for an uninterrupted period that includes a full tax year, as described by the IRS.
Think of it like planting roots. Renting a place for a few months while keeping your primary life in the United States looks temporary. Moving your household and shifting your routines looks different.
If you are a remote engineer working from Accra or Lisbon, then your residency status affects not only your federal return but also payroll reporting and possible state tax exposure.
Permanent Establishment Risk For Startups
Now shift to the employer’s side.
If a startup hires someone who works full-time from another country, then it may create a permanent establishment there. The OECD’s 2025 update makes clear that remote work can influence whether a fixed place of business exists.
Think of it like this: if your employee’s bedroom operates like your office, then tax authorities may treat it as one.
This is especially relevant for tech and AI startups hiring globally. A senior team member negotiating contracts abroad could trigger payroll requirements and corporate tax filings.
So founders should ask: Is the setup temporary or ongoing, and is the employee supporting operations or driving revenue?
A Smarter Way To Think About Remote Tax Residency
Tax residency in a remote-first world is not just about days on a calendar. It is about patterns, intent, and connections.
If you are an employee, then track your days and understand either the physical presence route or the residency route before relocating. If you are a founder, then map where your people work and how their roles function.
Remote work gives flexibility. However, tax systems still anchor to territory.
The goal is neither fear nor guesswork, but informed planning.