how is a resident alien defined in the united states 
an individual is classified as a resident alien of the u s for tax purposes if they meet either the green card test or the substantial presence test for the calendar year from jan 1 through dec 31 the green card test states that a person must either have a current green card or have had one in the previous calendar year the substantial presence test requires that they ve been in the u s for more than 31 days during the current year and 183 days during a three year period that includes the current year and the two years before 