How the substantial presence test works
The IRS treats you as a US tax resident for 2026 if you were in the US on at least 31 days in 2026, and your days in 2026, plus a third of your days in 2025, plus a sixth of your days in 2024, add up to 183 or more.
Example from the IRS: 120 days in each of three years gives 120 + 40 + 20 = 180 weighted days, so you don’t meet the test. A few more days in the current year would tip it over.
Spending long stretches in the US on an ESTA? Check your 90-day limit with the ESTA calculator too, and see US rules by passport.
Questions
What is the substantial presence test?
You are a US tax resident for a calendar year if you are in the US on at least 31 days that year, and the days this year plus a third of last year’s days plus a sixth of the year before add up to 183 or more.
What counts as a day?
Any day you are physically in the US, even for part of the day. Days don’t count if you commute from Canada or Mexico, are in transit for less than 24 hours, are crew on a foreign vessel, can’t leave because of a medical condition, or are an exempt individual such as an F or J student.
What is the closer connection exception?
If you were in the US on fewer than 183 days this year, have a tax home in another country and closer ties there, you can stay a non-resident even if you meet the test. You claim it on Form 8840.
Does a tax treaty change this?
It can. Many treaties have tie-breaker rules for people who are resident in two countries. Check the treaty with your country or ask an adviser.
Based on the IRS substantial presence test. Not tax advice.
More free calculators: Schengen 90/180 calculator · ESTA 90-day calculator · UK Statutory Residence Test calculator