A Substantial Presence Test is a test to verify if you can/will be considered a US resident for tax purposes.
You will be considered a United States resident for income tax purposes if you meet the Substantial Presence Test for the current tax year. To meet the substantial presence test, you must be physically present in the United States on at least:
- 31 days during the current year, and
- 183 days during the 3 year period that includes the current year and the 2 years immediately before that counting:
- All the days you were present in the current year, and
- 1/3 of the days you were present in the first year before the current year, and
- 1/6 of the days you were present in the second year before the current year.
For example: You were physically present in the United States on 120 days in each of the years 2015, 2016, and 2017. To determine if you meet the substantial presence test for 2018, count the full 120 days of presence in 2018, 40 days in 2017 (1/3 of 120), and 20 days in 2016 (1/6 of 120). Since the total for the 3-year period is 180 days, you are not considered a resident under the substantial presence test for 2018.