Free calculator · IRS Substantial Presence Test

Substantial Presence Test calculator

You meet the IRS Substantial Presence Test if you were in the US 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. Enter your trips or your day counts to see your total and how many days you have left.

Add your US trips for the tax year and the two years before, or switch to day counts.

USSubstantial presence · OK

0/ 183 weighted

0days left

Year	Days	Counts as
		× 1 =
		× ⅓ =
		× ⅙ =

When a calculator isn't enough

The IRS may ask you to prove it.

A calculator only knows what you type. Form 8840 asks for your exact days in the US, and a closer connection claim rests on where you really were. Proofstay records the country, state or province you are in every day on your iPhone, proofs each record the moment it is made, and turns any year into a day-by-day report for your accountant. Free to record.

See how Proofstay works →

How the test works

31 days this year, 183 over three

The Substantial Presence Test decides whether someone who is not a US citizen or green card holder is treated as a US resident for federal income tax. You meet it for a calendar year if both are true:

you were physically in the US on at least 31 days in that year, and
the days in that year, plus one third of the days in the year before, plus one sixth of the days in the year before that, add up to 183 or more.^[1,2]

What counts as a day

Any day you are in the US, even for an hour, counts as a full day. The day you fly in and the day you fly out both count.^[2,3] Fractions are not rounded: 100 days last year count as 33⅓.

Example: 120 days a year

This is the IRS's own example. You were in the US 120 days in each of 2023, 2024 and 2025. For 2025 the total is 120 + 40 (⅓ of 120) + 20 (⅙ of 120) = 180. That is under 183, so you don't meet the test for 2025. Three more days in 2025 would have tipped it.^[1]

Example: a Canadian snowbird in Florida

You winter in Florida from 1 November to 31 March every year. That is 152 days in 2024 (a leap year), 151 in 2025 and 151 in 2026. For 2026: 151 + 50⅓ + 25⅓ = 226⅔. You meet the test, even though you never spent 183 days in the US in any single year. Because you were there fewer than 183 days in 2026, you can still claim the closer connection exception on Form 8840 (see below).

Exceptions

Days that don't count, and the closer connection

Days that don't count

Days you commute to work in the US from Canada or Mexico, if you do so regularly.
Days in the US for less than 24 hours while in transit between two places outside the US.
Days as a crew member of a foreign vessel.
Days you couldn't leave because of a medical condition that arose while you were in the US.
Days as an exempt individual: for example a foreign government official, a teacher or trainee on a J or Q visa, or a student on an F, J, M or Q visa.^[1,2]

This calculator counts every day you enter. Leave out the days above if they apply to you.

The closer connection exception (Form 8840)

If you meet the test but were in the US fewer than 183 days in the year, you can still be treated as a nonresident if, for the whole year, you kept a tax home in another country and had a closer connection to it than to the US (your home, family, belongings, driver's license, bank and where you vote all point there), and you hadn't applied for a green card.^[4]

You claim it on Form 8840. Attach it to your US return if you file one; if not, mail it by the return's due date, which for most snowbirds with no US wages is 15 June. A late form can lose the exception.^[3,4] If you were in the US 183 days or more in the year itself, this exception is not available, though a tax treaty may still help: ask a cross-border tax adviser.

Not the same as the 182-day visitor rule

Canadian visitors are generally allowed up to about six months in the US in a 12-month period, and many snowbirds keep under 182 days^[5] (how long Canadians can stay). That is an immigration limit on a rolling 12 months. The Substantial Presence Test is a tax test on calendar years. When you enter trips, the calculator shows both.

Sources

IRS, Substantial presence test. Checked 25 Oct 2026.
IRS, Publication 519, U.S. Tax Guide for Aliens. Checked 25 Oct 2026.
IRS, Form 8840 (2025) and instructions (PDF). Checked 25 Oct 2026.
IRS, Closer connection exception to the substantial presence test. Checked 25 Oct 2026.
Government of Canada, Travel advice for the United States: entry, registration, length of stay. Checked 25 Oct 2026.

FAQ

Substantial Presence Test questions

How is the Substantial Presence Test calculated?

Add all the days you were in the US this year, one third of the days last year and one sixth of the days the year before. If the total is 183 or more and you were in the US at least 31 days this year, you meet the test and are treated as a US resident for tax purposes, unless an exception applies.

Does a partial day count as a day in the US?

Yes. Any day you are physically in the US, even for part of it, counts. The exceptions are days in transit between two foreign places for less than 24 hours, regular commuting from Canada or Mexico, days as crew on a foreign vessel, days you couldn't leave because of a medical condition that arose in the US, and days as an exempt individual such as an F or J student.

I meet the test but spent fewer than 183 days in the US. Am I a resident?

Not necessarily. If you were in the US fewer than 183 days this year, kept a tax home in another country all year and had a closer connection to it, you can claim the closer connection exception by filing Form 8840. File it on time: with your US return, or by the return's due date if you don't file one.

Is the 182-day rule for Canadian snowbirds the same thing?

No. The Substantial Presence Test is an IRS tax test that weights three calendar years. The 182-day figure is the immigration guideline for how long Canadian visitors may stay in a rolling 12 months. A snowbird can be fine on one and still meet the other, which is why many file Form 8840 every year.

Does the count reset every year?

Partly. Each year is tested on its own, but last year and the year before still count at one third and one sixth. Long winters in the US add up over three years even if no single year comes close to 183 days.

Are my trips stored anywhere?

Only in your own browser, so they are there when you come back. Nothing is sent to a server.

More free calculators