Tax & Residency guide
The 183-day rule, by country
What the 183-day rule means for tax residency, why most countries use it, and where it differs — Portugal, Spain, UK, Germany, France, US, and more.
If you spend 183 or more days in a country in a calendar year, most tax systems will treat you as a tax resident there. That triggers worldwide income reporting in many cases — not just income earned inside that country.
But “the 183-day rule” is not one rule. Each country has its own variant. Same number, different mechanics. This guide breaks down the most common forms.
What 183 days actually means
183 days is roughly half a year + one day. Tax authorities use it as a bright-line proxy for “your real life is here.”
In practice the mechanics vary along five axes:
- What year? Calendar year, tax year, or rolling 12-month window
- What counts as a day? Full days, parts of days, days of physical presence with exceptions for medical / transit / family obligations
- What other tests apply? Most countries have additional tests that can make you a resident with fewer than 183 days (ties, home, family, work)
- What about averaging? The US averages over 3 years; some others don’t
- What’s the consequence? Worldwide income tax (most countries) vs. only local-source income (a few)
How it works in major countries
Portugal
- 183 days of presence in any 12-month period → tax resident
- Or: habitual residence in Portugal on 31 December of the year
- Worldwide income tax (NHR / IFICI regime may reduce this for new arrivals — see Portugal NHR guide)
Spain
- More than 183 days in a calendar year → tax resident
- Sporadic absences count toward 183 unless tax residence elsewhere is proven
- “Centre of economic interests” test can trigger residence with fewer days
- Worldwide income tax, including the controversial wealth tax
United Kingdom
- The Statutory Residence Test (SRT) replaces a simple 183-day rule
- 183+ days automatically makes you resident, but the SRT can make you resident with as few as 16 days if you have enough UK ties
- See the UK SRT guide
Germany
- More than 183 days of presence → tax resident
- Or: a “habitual abode” (Wohnsitz) — a home permanently available — at any time during the year
- Worldwide income tax
France
- 183+ days → tax resident
- Or: main home, principal economic activity, or center of economic interests in France
- Worldwide income tax
United States
- The 183-day rule is replaced by the Substantial Presence Test — a weighted formula across the current and prior two years
- See the US Substantial Presence Test guide
- Citizens are taxed on worldwide income regardless of residence
UAE
- 183 days in any 12-month period → tax resident
- Or: 90 days + UAE-based home / income / family
- No personal income tax (residence cert is mainly for tax-treaty access)
Cyprus
- 183 days in a calendar year → tax resident
- Or: 60-day rule — see Cyprus 60-day rule
”But I only spent 180 days, am I safe?”
Not necessarily. Most countries have second-tier tests that can establish residence with fewer days:
- A permanent home available to you
- A spouse or dependent children living there
- Your principal economic activity
- Your “centre of vital interests” (a treaty term that captures family, social, economic ties)
If you split time across multiple countries, you can become resident in more than one under their domestic laws. Tax treaties then run a tiebreaker (permanent home → centre of vital interests → habitual abode → nationality) to assign a single residence for treaty purposes.
The practical implications
If you’re close to 183 days in any country:
- Track precisely. A trip you forgot can push you over.
- Be careful about year-end travel. Arriving 30 December vs. 2 January can change your residence status.
- Document your time elsewhere. If a tax authority asks, you need flight records, accommodation receipts, and ideally a tax residency certificate from another country.
- Get advice early. Tax residence is hard to undo retroactively.
DaysAbroad tracks your day count per country automatically, with multi-year history and a Schengen-aware view — so you don’t get a nasty surprise from a tax authority three years later.