US Tax Residency TestDays that do not count
The IRS page (read on 13 November 2026) says you are treated as present on any day you are physically present in the US at any time during the day, except:
- Days you commute to work in the US from a residence in Canada or Mexico, if you regularly commute.
- Days of less than 24 hours when you are in transit between two places outside the US.
- Days as a crew member of a foreign vessel.
- Days you cannot leave the US because of a medical condition that develops there.
- Days as an exempt individual.
Exempt individuals
This does not mean exempt from tax. It means: a foreign government-related individual on an A or G visa (not A-3 or G-5); a teacher or trainee on a J or Q visa who substantially complies with the visa; a student on an F, J, M or Q visa who substantially complies with the visa; a professional athlete temporarily in the US to compete in a charitable sports event.
If you leave out days as an exempt individual or because of a medical condition you must include Form 8843 with your return, or send it by the due date if you need not file one. Without a timely Form 8843 you cannot exclude those days, unless you can show by clear and convincing evidence that you took reasonable steps to comply.
The United States here means the 50 states, the District of Columbia and US territorial waters, not US territories or airspace.
Common questions
Do days of transit count?
Days in the US of less than 24 hours while in transit between two places outside the US do not count.
What if I cannot leave because I fall ill?
Days you cannot leave because of a medical condition that develops in the US do not count, but Form 8843 must be filed.
Source
- Internal Revenue Service, "Substantial presence test", irs.gov, read on 13 November 2026.
Rules read on 13 November 2026 from the IRS website. They may have changed since. This site is independent, not connected with the IRS, and gives arithmetic, not tax advice.