14 Tax Issues Faced by Non-US Citizens Working in the United States
1) When am I considered a US tax resident for tax purposes (ie how many days spent in the US)?
You will be considered a United States resident for tax purposes if you meet the substantial presence test for the calendar year. To meet this test, you must be physically present in the United States (U.S.) on at least:
1. 31 days during the current year, and
2. 183 days during the 3-year period that includes the current year and the 2 years immediately before that, counting:
– All the days you were present in the current year, and
– 1/3 of the days you were present in the first year before the current year, and
– 1/6 of the days you were present in the second year before the current year.
2) Do I have to declare my worldwide income (such as my foreign earned & unearned income)?
Once you meet the Substantial Presence test you become a subject to the same filing obligations as U.S. citizen, i.e. you are required to declare your worldwide income.
Whole Story at TFX.