At a glance
- The test
- A stay of at least 30 days with paid work, or at least 90 days without (DBG Art. 3 Abs. 3). Cantons apply the same figures (StHG Art. 3).
- Period
- One stay, not a calendar year. Temporary interruptions are ignored. The stay can cross a year end.
- What counts as a day
- The law gives no definition. Physical presence is what is needed; no intent to stay is required.
The rule
Under Art. 3 DBG and Art. 3 StHG, a person is liable to tax in Switzerland on worldwide income if they have tax domicile or a tax stay there. A tax stay exists where the person, ignoring temporary interruptions, stays in Switzerland at least 30 days and works for pay, or at least 90 days without working.
The Federal Supreme Court has said the stay must be more or less continuous: one block or a small number of blocks. Short absences do not matter while the person keeps a real connection to Switzerland. Presence is enough, with no intent to stay (2C_186/2020).
A stay for school, or for treatment in a medical institution by a person with a foreign domicile, does not create a tax stay (Art. 3 Abs. 4 DBG). Liability from a tax stay applies pro rata, for the days of the stay.
Domicile is a separate route and is not a day count. Treaties often take priority in international cases.
How Atrium counts it
Atrium treats each recorded run in Switzerland as one stay and counts any presence on a calendar day. It joins absences of up to 30 days into one stay and counts the whole span, including those absences. The 30 days is Atrium's own cautious figure. The law sets none.
If a stay has paid work recorded, or the work question is unanswered, Atrium uses 30 days. It uses 90 days only when you record that there was no work. It shows how many days are left before the stay reaches that figure.
Atrium shows the stay that reaches into the current year, or the next one recorded. It does not judge whether remote work for a foreign employer counts as paid work in Switzerland, or tests domicile, canton or treaties.
What catches people out
- The test follows one stay, so a stay that began in November counts in full when it runs into January.
- Short trips out of Switzerland during a stay may not stop it, if the connection to Switzerland continues.
- The 30-day figure applies where there is paid work in Switzerland. Whether remote work counts is a question for your adviser.
- Outpatient medical treatment is not a protected special purpose. In 2C_186/2020 the court counted the stay anyway.
- Living in Switzerland (domicile) can create liability with no day count at all.
Cases
Medical treatment in Zurich, 2014
Swiss Federal Supreme Court (II. öffentlich-rechtliche Abteilung) · 2020 · 2C_186/2020, judgment of 28 December 2020 Source
A man who left Zurich for the Bahamas in 2006, and did not work in Switzerland, spent January to 14 October 2014 in Zurich for medical treatment, about 50 days of it in hospital. Zurich taxed him for the whole year. The Court held that over 90 days of presence created a tax stay, and that outpatient treatment is not the special purpose in Art. 3 Abs. 4 DBG. But the stay ended when he left on 14 October, so it sent the case back for reassessment to that date.
Presence of over 90 days was enough, whatever the reason. His return in mid-December, two months later, was not a temporary interruption, so the first stay had ended on 14 October.
Sources
- Swiss Federal Supreme Court 2C_186/2020 (28 December 2020)
- ESTV, Steuerbegriffe: Subjektive Steuerpflicht (September 2021)
- Bundesgesetz über die direkte Bundessteuer (DBG), Fedlex
Based on the sources above, last reviewed on 2026-10-04. Educational content, not tax advice. Atrium counts days; whether those days make you resident is for you and your adviser to decide.