Am I a resident alien for US tax purposes?

A day-count test for US tax residency. You meet it if you were in the US on at least 31 days this year and your weighted total is at least 183 days: every day this year, plus one-third of the days last year, plus one-sixth of the days the year before (IRS Publication 519). Meeting it makes you a resident alien for tax purposes unless an exception applies. The IRS’s own example: 120 days in each of three years totals 180, so that person is not a resident.

Not while you are an exempt individual. Days as a student on an F, J, M or Q visa, and days as a J or Q teacher or trainee, do not count if you substantially comply with the visa. Students are exempt for five calendar years, and any part of a year counts as a year; in the sixth, their days count unless they show they do not intend to reside permanently in the US. Teachers and trainees are not exempt if they were exempt as a teacher, trainee or student in 2 of the 6 preceding calendar years. Exempt individuals file Form 8843.

You are present on any day you were physically in the US at any time during the day, so a partial day counts. Days in transit through the US for less than 24 hours between two foreign places, days commuting from Canada or Mexico if you regularly commute, days as crew of a foreign vessel, days you could not leave because of a medical condition that arose here, and exempt-individual days do not count (Publication 519).

Even if you meet the test, you can be treated as a nonresident if you were in the US fewer than 183 days this year, kept a tax home in a foreign country all year, and had a closer connection to it than to the US. You cannot use it if you applied for a green card, or took other steps to become a permanent resident, that year. You claim it on Form 8840 by the due date of your Form 1040-NR.

A tax year in which you were both a nonresident and a resident alien, usually the year you arrive or leave (Publication 519, chapter 6). If you meet the test and were not a resident last year, you are a resident only from your residency starting date, which is your first day in the US that year (days as an exempt individual are not days here), and a nonresident before it; if that day is January 1 there is no nonresident part. If you leave for good, your residency ends on December 31 unless you qualify for an earlier date, the last day you were in the US, by keeping a tax home and closer connection abroad afterwards. A dual-status return cannot use the standard deduction and, with limited exceptions (see “Choosing Resident Alien Status” in Publication 519), cannot be filed jointly. It could not be e-filed for 2025; check the current year’s rule. This page does not compute the dates.

You tell your employer which you are so it can withhold correctly. Residents are withheld like citizens. A nonresident’s wages are subject to graduated withholding but follow special Form W-4 instructions (IRS Notice 1392), and US dividends face 30% withholding unless a treaty lowers it (most bank and portfolio interest is not withheld on). Nonresident F, J, M or Q visa holders generally do not pay Social Security and Medicare tax on work that carries out the purpose of their visa, such as on-campus work or practical training; once they become residents those taxes are withheld even though the visa is the same.