Substantial Presence Test for Aliens (1040notes.com)
You will be considered a U.S. resident for tax purposes if you meet the substantial presence test for calendar year 2013. To meet this test, you must be physically present in the United States on at least:
- 31 days during 2013, and
- 183 days during the 3-year period that includes 2013, 2012, and 2011, counting:
- All the days you were present in 2013, and
- 1/3 of the days you were present in 2012, and
- 1/6 of the days you were present in 2011.
Do not count as days that you were present in the U.S.:
- Days you commute to work in the United States from a residence in Canada or Mexico, if you regularly commute from Canada or Mexico.
- Days you are in the United States for less than 24 hours, when you are in transit between two places outside the United States.
- Days you are in the United States as a crew member of a foreign vessel.
- Days you are unable to leave the United States because of a medical condition that develops while you are in the United States.
- Days you are an exempt individual (your first five calendar years in F, J, Q or M student status or your first two calendar years in J non‐student status)
If your countable days total 183, then you are considered a resident for tax purposes. Use the same rules as citizens to determine whether you need to file (Filing requirements for tax residents).
If you do not meet the substantial presence test, you must file as a non resident (Filing requirements for nonresidents).
"I am a human being, I consider nothing that is human alien to me."
-Publius Terentius Afer (195/185–159 BC), Roman playwright and slave