How it works
How Residia works.
Residia tracks the rules that determine your tax residency status — not just how many days you've spent in each country. Here's how.
Three steps to clarity.
Log your stays
Add each country you've visited with your entry and exit dates. You can log past trips to build a history or add upcoming trips to plan ahead. Residia handles partial days, same-day trips, and overlapping travelers in a household.
Pick your rules
Choose which tax residency rules apply to your situation. If you hold an Italian passport with UAE income, you'll want the Italy 183-day rule and the Italian blacklist flag. Establishing Spanish residency? Add the no-other-country constraint. UK-connected and spending time there? Add the SRT 90-day threshold.
See where you stand
Residia runs the calculations against every rule you've selected and shows your current status — days remaining, thresholds at risk, and rules you've already satisfied. Use the scenario planner to add a hypothetical trip and see the impact before you book.
Pre-built rules
Rules Residia tracks today.
Three of the rules available today — with more country-specific rules coming.
Italy — 183-day rule
Applies to
Italian passport holders living or working abroad
Residia tracks
Days spent in Italy across the calendar year. Stay under 183 to avoid Italian tax residency. If your income comes from a blacklisted country (e.g. UAE), the burden of proof reverses — Residia flags this separately.
UK — 90-day SRT threshold
Applies to
People with UK connections spending time in the UK
Residia tracks
Days in the UK across the tax year. Under the UK Statutory Residence Test, spending 91 or more days with sufficient UK ties can trigger UK tax residency. Residia tracks your running total and warns as you approach the threshold.
Spain — residency, no other country
Applies to
People establishing Spanish tax residency
Residia tracks
Whether you are simultaneously tax resident in another country. Spanish residency requires that Spain is your primary tax home — holding tax residency elsewhere is incompatible. Residia flags any conflicting residency based on your day counts across countries.
+ Italy blacklist flag, Schengen 90/180 rolling window, Cyprus 60-day non-dom, UAE residency, and more.
Common questions.
Can I request a custom rule for my specific situation?+
Yes. If your tax residency situation involves a rule not already covered — a specific country threshold, a bilateral treaty provision, or a unique combination of conditions — you can request a custom rule tailored to your needs. Use the request option in the Rules section of the console.
What is the 183-day tax residency rule?+
Most countries consider you a tax resident if you spend 183 or more days there in a calendar year. This is the most common threshold in Europe. Italy, Spain, France, Germany, and many others use it. Residia tracks your day count against this threshold and warns before you cross it.
How does the UK Statutory Residence Test work?+
The UK SRT determines whether you are a UK tax resident based on days spent in the UK combined with your UK ties (family, accommodation, work, 90-day tie). Spending fewer than 16 days means automatic non-residence. Between 16 and 182 days, residency depends on how many UK ties you hold. The 90-day tie is triggered if you spent 91 or more days in the UK in either of the previous two tax years.
What does "no other country" mean for Spanish residency?+
Spanish tax residency requires Spain to be your primary tax home. You cannot simultaneously hold tax residency in another country — Spanish law treats dual tax residency as incompatible. If your day counts in another country reach that country's residency threshold, you have a conflict that needs resolving through a tax adviser.
How does the Schengen 90/180 rule work?+
Non-EU nationals (US, UK, Australian, and other third-country passports) can spend a maximum of 90 days in the Schengen Area within any rolling 180-day window. The window is not reset every 6 months from a fixed date — it is calculated on a rolling basis. Ireland and Cyprus are EU members but not part of Schengen; days there do not count toward your quota. Residia correctly excludes both.