How to Save U.S. Taxes for Nonresident Aliens The green card test and the substantial presence test are the two tests used by IRS for determining your alien status. If you meet either one's criteria, you're considered a resident alien for income tax purposes; otherwise, you're classified as a nonresident alien.
If you are a foreigner with a green card, which means that the US Citizenship and Immigration Service enable you to reside in the country lawfully, you are a foreign resident. Suppose, however, that you do not have a green card and spend a minimum of 31 days in the US during the current tax year and a total of 183 days in the previous three tax years (inclusive of the current tax year). In that case, the physical presence test is usually completed, and you are still regarded as a resident alien.
Nonresident Taxes