Who this is for
Anyone who splits the year between countries — remote workers, retirees, people with homes in two places — and wants to understand when the days they spend somewhere start to make them tax resident there.
How three countries actually use it
Across the EU, the European Commission puts it this way: you will usually be tax resident where you spend more than six months a year. "Usually" is doing a lot of work in that sentence.
- Spain: you are tax resident if you spend more than 183 days in Spain in the calendar year — or if the main centre of your business or economic interests is in Spain, however few days you spend there. Sporadic absences still count as days in Spain unless you prove tax residence elsewhere.
- United Kingdom: 183 days or more in the UK tax year, which runs from 6 April to 5 April, makes you resident automatically. With fewer days you can still be resident, depending on your ties to the UK.
- United States: the Substantial Presence Test does not use a single year. It adds up days over three years with weights, and 183 weighted days, with at least 31 in the current year, can make you a US tax resident.
- When two countries both consider you resident, a double taxation agreement between them normally decides which one has the right to treat you as resident.
Why staying under 183 days is not enough
Say you spend 150 days in Spain in a calendar year, but you run your business from Spain and most of your income comes from Spanish clients. You are under 183 days, yet Spain can still treat you as tax resident because your main economic interests are there. The day count is one test, not the only one.
Common questions
If I stay under 183 days in every country, am I tax resident nowhere?
Rarely. Most countries have tests beyond the day count, such as where your home, family or economic interests are, and you normally remain tax resident in your home country if you spend less than six months a year abroad.
Is the 183 counted per calendar year?
It depends on the country. Spain uses the calendar year, the UK uses its tax year from 6 April to 5 April, and the US weights days across three calendar years.
Does the 183-day rule have anything to do with the Schengen 90 days?
No. The Schengen 90/180 rule is an immigration limit on how long you may stay; the 183-day rule is a tax threshold. You can respect one and still trigger the other.
What if two countries both say I am resident?
Check whether they have a double taxation agreement. These treaties include tie-breaker rules — looking at your permanent home and where your personal and economic ties are strongest — to decide which country treats you as resident.
Check it at the source
These are the official pages this guide is based on. Tax residency depends on your full circumstances, so take advice before acting on it.