Tax residency in United States: the 183-day rule
High confidenceReviewed in September 2026
The short answer
183days in three years, weighted
- Window
- Three years, weighted
- How it counts
- Any presence during the day
- Direction
- Reaching the threshold makes you resident
How the days are counted
Add every day of this year, a third of last year's days and a sixth of the year before; if the total reaches 183 and you were also present 31 days this year, you are a tax resident. Some days do not count and the app cannot spot them: under 24 hours in transit between two other countries, daily commutes from Canada or Mexico, crew of a foreign vessel, days held there by an illness that started in the US and days on an exempt visa (F, J, M, Q and government staff). Subtract those yourself.
Even then the count does not decide on its own: a green card makes you resident with no counting at all, and treaties can change the answer.