Your US days

Days physically present in the US this calendar year (any part of a day counts as a full day, so count arrival and departure days)

Days present last year

Days present the year before that

Days that don't count (read before you total)

A handful of day types are excluded from the count by statute:

Regular commuters from Canada or Mexico: days you commute to work in the US from a residence in Canada or Mexico, if you regularly commute.
In transit: days you are in the US for less than 24 hours while in transit between two places outside the US.
Crew members: days in the US as a crew member of a foreign vessel.
Medical condition: days you could not leave because of a medical condition that arose while you were in the US.
Exempt individuals: days as a student on an F, J, M or Q visa, a teacher or trainee on a J or Q visa, a foreign government-related individual, or a professional athlete temporarily in the US to compete in a charitable sports event. Exempt status is time-limited and has its own rules.

Excluding exempt-individual or medical days requires filing Form 8843. If some of your days fit these categories, enter them below and the calculator subtracts them from this year's count. Apply the same logic yourself to the two prior years by entering net countable days above.

Days this year you believe don't count

Your result

Countable days this year0

Last year × 1/30

Year before × 1/60

Weighted total (vs 183)0

Enter your days above

The test has two parts: at least 31 days in the US this year, AND a weighted three-year total of 183 or more. Miss either part and you don't meet the substantial presence test.

Assumptions this count makes: your day totals are accurate and already follow the partial-day rule (any part of a day in the US counts as a full day); the "days that don't count" subtraction is your own good-faith estimate, and exempt-individual or medical exclusions only hold up if Form 8843 is filed; fractions in the weighted total are compared against 183 without rounding, which is how the regulation does it. The tool ignores the green card test (a separate, independent path to US residency), first-year and dual-status start dates, treaty elections, and state residency rules, which have their own day counts. It's an estimate, not advice; a real residency file works through all of this properly.

How this calculator works (the actual rules)

The two-part test: you meet the substantial presence test if you were present in the US on at least 31 days during the calendar year, and the weighted sum of your days over three years equals or exceeds 183. The multipliers come straight from the statute: current year days count in full, first preceding year days count at 1/3, second preceding year days at 1/6 (26 USC 7701(b)(3)(A)).
Partial days are full days: you are treated as present in the US on any day you are physically present at any time during the day (26 USC 7701(b)(7)(A); IRS, Substantial Presence Test). An evening flight in still burns a whole day.
Fractions are not rounded: the regulation is explicit that fractional days from the 1/3 and 1/6 multipliers "will not be rounded to the nearest whole number" before comparing to 183 (26 CFR 301.7701(b)-1(c)(1)). A weighted total of 182.83 does not meet the test; this calculator compares the exact figure.
Days that don't count: regular commuters from Canada or Mexico (26 USC 7701(b)(7)(B)), less-than-24-hour transit days (7701(b)(7)(C)), foreign vessel crew days, medical-condition days, and days as an exempt individual, meaning students on F, J, M or Q visas, teachers or trainees on J or Q visas, foreign government-related individuals, and professional athletes at charitable events (7701(b)(5)). Exempt and medical exclusions require Form 8843.
The closer connection exception (the snowbird escape hatch): if you meet the test but were in the US fewer than 183 days this year, you can still be treated as a nonresident if you kept a tax home in a foreign country all year and a closer connection to that country than to the US (26 USC 7701(b)(3)(B)). You claim it on Form 8840, attached to your return or filed on its own by the return deadline; file it late without good cause and the exception is off the table. It's also unavailable if you applied for, or took steps toward, a US green card (IRS, Closer Connection Exception).
At 183 actual days, the exception is gone: spend 183 or more actual days in the US in one year and the closer connection route closes. What remains is the residency tie-breaker in Article IV of the Canada-US tax treaty, which is a facts-and-circumstances analysis, not a form you file casually.
Full walk-throughs: your first year of US taxes as a Canadian, what happens to RRSPs, TFSAs and account reporting, and the companion tool for the other side of the move, the Canadian departure tax calculator.

This tool provides general information and rough estimates only, not tax advice for your situation. Methodology checked against the statute, regulation and IRS pages linked above; rules current to the 2026 filing year.

Substantial Presence Test Calculator: Count Your US Days

Your US days

Your result

Email me the first-year US tax guide

How this calculator works (the actual rules)

Close to the line, or already over it?