When does a non-resident become a United States Tax Resident?

If the Non-resident is neither a dual citizen of the US nor holds a green card, then the Substantial Presence Test applies. A Non-resident meets the Substantial Presence Test if he is physically present in the US for 31 days during the current calendar year AND he is physically present in the US for 183 days or more in the current and prior two years with the days of physical presence counted as follows: all the days in the current year, 1/3 of the days last year, and 1/6 of the days two years ago.

Foreign Tax Home exception: A Non-resident may establish his US nonresident status if he is in the US less than 183 days in the current year disregarding his time in the US in the prior two years. He must establish that he has a closer connection to their home country than to the US during the current year as evidenced by factors such as where his permanent home is, where his financial accounts, church and cultural organizations are, where he votes, and where his driver’s license is issued. To claim this exception he needs to file Form 8840 along with his US nonresident tax return.

Tax Treaty exception: A Non-resident may establish his US nonresident status if he is in the US for 183 days or more in the current year by asserting that he is a nonresident under the provisions of Article 4 of the Treaty. To claim this exception he needs to file Form 8833 along with his US nonresident tax return. Nonresidence may be harder to assert if he’s in the US all year than for, say, 220 days.

Days not included in physical presence: Days spent in the US as a commuter from a residence in their home country, stays of less than 24 hours while in transit between other countries, days spent while unable to leave due to a medical condition arising after arrival, or days as an exempt individual (a foreign government-related individual, visitor under a specific academic visa, or athlete participating in a charitable event). Days of physical presence would, however, include visits to obtain medical treatment for a condition existing prior to arrival.