Substantial Presence Test: How Days Make You a U.S. Resident
The weighted 183-day formula, which days don't count, and the two ways a Canadian who meets it stays a nonresident
Reviewed by the Fairlight Accounting cross-border tax team — U.S. & Canadian Tax Desks
The substantial presence test decides whether a foreign national is a U.S. tax resident by counting days: at least 31 days this year and 183 days over three years, counting all of this year's days, one-third of last year's, and one-sixth of the year before. Meeting it means tax on worldwide income unless an exception applies.
On this page
The formula
| Year | Weight | Example: 150 days each winter |
|---|---|---|
| Current year | Every day | 150 |
| Prior year | One-third | 50 |
| Year before | One-sixth | 25 |
| Total | — | 225 — meets the test |
So a snowbird spending about 122 days a year (122 + 40.7 + 20.3 = 183) meets the test; one spending 120 days a year doesn't (120 + 40 + 20 = 180). Any part of a day counts as a day.
Days that don't count
Days in transit between two foreign points (less than 24 hours in the United States), days a person couldn't leave because of a medical condition that arose in the United States (with Form 8843), days as an exempt individual (certain students, teachers, trainees, and foreign government-related individuals — generally with Form 8843), and days commuting to work in the United States from a home in Canada or Mexico (a regular commuter — one who commutes on more than 75 percent of workdays).
The exits
| Situation | How to stay a nonresident |
|---|---|
| Meets the test but under 183 days in the current year | Closer connection exception — Form 8840 by June 15 (the Form 8840 guide) |
| 183 days or more in the current year | The treaty tie-breaker (Article IV) — Form 8833 with Form 1040-NR (the Form 8833 guide) |
| Green card holder | Not this test — a lawful permanent resident is a resident by the green card test |
Why the count matters
Residency changes what the United States taxes: a resident reports worldwide income on Form 1040 and files FBAR and Form 8938 for Canadian accounts; a nonresident reports only U.S.-source and effectively connected income on Form 1040-NR. Provincial health plans limit time away too — Ontario, for example, requires 153 days in the province in any 12-month period (up to 212 days away), and other provinces generally require about six months a year.
Frequently asked questions
How many days can a Canadian stay in the U.S. without becoming a tax resident?
Fewer than about 122 days a year, every year, keeps the three-year weighted total under 183. Above that, file Form 8840 each year if under 183 days in the current year.
Do partial days count?
Yes — any part of a day in the United States counts as a full day, apart from the listed exceptions.
Is the substantial presence test the same as the immigration 182-day rule?
No. Immigration rules (and the border's six-month visitor limit) are separate from the tax test, though the numbers are similar.
What if I'm a resident under both countries' rules?
The treaty's tie-breaker decides — permanent home, center of vital interests, habitual abode, then citizenship — claimed on Form 8833.
Official sources
The IRS explains: “To meet this test, you must be physically present in the United States (U.S.) 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 …” — Internal Revenue Service, Substantial presence test, https://www.irs.gov/individuals/international-taxpayers/substantial-presence-test
The IRS explains: “Use Form 8840 to claim the closer connection to a foreign country(ies) exception to the substantial presence test.” — Internal Revenue Service, About Form 8840, Closer Connection Exception Statement for Aliens, https://www.irs.gov/forms-pubs/about-form-8840
Next step
Fairlight Accounting is a cross-border accounting and tax practice with a U.S. Tax Desk and a Canadian Tax Desk. Our U.S. Tax Desk and Canadian Tax Desk handle U.S. residency determinations for Canadians — day-count analysis, Form 8840 and Form 8843 filings, treaty tie-breaker positions, and the transition to U.S. resident or nonresident returns. See pricing or book a call.
Cross-border taxes, handled in one place
U.S. and Canadian filings prepared together by our U.S. and Canadian Tax Desks.
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