Am I a US Tax Resident?

An individual meets the Substantial Presence Test for a calendar year if they were physically present in the United States on at least thirty-one days during the current year, AND on at least one hundred eighty-three days across a three-year period counting: all the days present in the current year, one-third of the days present in the first preceding year, and one-sixth of the days present in the second preceding year. Both conditions must be satisfied — thirty-one current-year days alone is not enough, and a large weighted total does not count if the current year falls under thirty-one days.

A person is treated as present in the United States on any day they are physically present in the country at any time during that day; a few hours counts as a full day. Four categories of day are excluded: days commuting to work from a residence in Canada or Mexico where the person regularly commutes; days in the United States for less than twenty-four hours while in transit between two places outside it; days present as a crew member of a foreign vessel; and days unable to leave because of a medical condition that developed while in the United States. A layover on the way to somewhere else generally does not count — a weekend visit does.

A student temporarily present on an F, J, M or Q visa who substantially complies with the visa's requirements is an 'exempt individual', and days present as an exempt individual do not count toward the Substantial Presence Test at all. This applies for up to five calendar years: a person ceases to be exempt on this basis once they have been exempt as a student, teacher, trainee or exchange visitor for any part of more than five calendar years. Note the counting is by CALENDAR YEAR and by any part of it — arriving in December burns a full year of the five.

A teacher or trainee temporarily present on a J or Q visa is likewise an exempt individual, but on a much tighter limit than a student: the exemption is unavailable if the person was exempt as a teacher, trainee or student for any part of two of the six calendar years preceding the current year. A narrow extension exists where a foreign employer paid all of the person's compensation. Because student years and teacher/trainee years count toward each other's limits, a person who studied in the United States and later returned on a J visa can find the exemption already spent.

A person excluding days of presence as an exempt individual must file Form 8843, Statement for Exempt Individuals and Individuals With a Medical Condition, for each year they claim the exclusion. Being on a student or exchange visa does not by itself exclude the days; the form is how the exclusion is asserted. A student who never filed Form 8843 has an argument to make rather than a settled position.

The Substantial Presence Test is only one of two routes to US tax residency. A lawful permanent resident — a green-card holder — is a US tax resident under the separate Green Card Test regardless of how few days they spend in the United States, until that status is formally abandoned or revoked. Running a day count is therefore pointless for a green-card holder: the answer is already yes, and the foreign-account and foreign-gift filings apply.