Substantial Presence Test Calculator for Workations
Working from the United States for part of the year? Enter the days you were physically present in the current year and the two years before, and the calculator applies the IRS substantial presence test: at least 31 days this year and 183 days on the weighted three-year count. This page covers the U.S. federal test only. Other countries set their own residency rules, which are not modelled here.
The substantial presence test is the IRS day-count rule that decides whether a person who is not a U.S. citizen or green card holder is a U.S. resident for tax purposes. You meet it if you are physically present in the United States for at least 31 days in the current year and 183 days over a three-year period, counting all of this year's days, one third of last year's and one sixth of the days from the year before that.
How the substantial presence test calculator counts days
| Year | Days counted | Example (120 days each year) |
|---|---|---|
| Current year | All days | 120 |
| First year before | 1/3 of the days | 40 |
| Second year before | 1/6 of the days | 20 |
| Weighted total | Must reach 183, with at least 31 days in the current year | 180: test not met |
Worked example: 120 days in each of three years gives 120 + 40 + 20 = 180, just under 183, so the test is not met. With the same prior years, the 123rd day in the current year tips the total to 183. A second example: 95 days this year after 240 and 300 days in the two earlier years gives 95 + 80 + 50 = 225, so the test is met even though this year's stay was only about three months.
Days that do not count
The IRS does not count days you commute to work in the United States from a home in Canada or Mexico, days in transit for less than 24 hours between two places outside the United States, days as a crew member of a foreign vessel, days you could not leave because of a medical condition that arose while you were there, and days as an exempt individual. Exempt individuals include certain foreign-government-related individuals, teachers and trainees on J or Q visas, students on F, J, M or Q visas, and professional athletes competing in a charitable sports event; they generally claim the exclusion on Form 8843. Put the total of such days in the last field and the calculator subtracts them from this year's count.
Workations and the 183-day idea
Remote workers often quote a "183-day rule". For the United States that is misleading in both directions: the weighted count means you can become resident with far fewer than 183 days in a single year, as the second example shows. Even when you meet the test, the IRS can still treat you as a nonresident under the closer connection exception if you were present less than 183 days during the year, kept a tax home in a foreign country for the entire year and had a closer connection to that country than to the United States. Other countries apply their own tests, and a tax treaty may decide the outcome when two countries both claim you.
What this tool does not do
It does not work out tax owed, apply a treaty, test state residency or cover any country other than the United States. Use it to see where you stand on the federal day count, then confirm your position with a qualified adviser.
Source: IRS, Substantial Presence Test and IRS, Closer Connection Exception. The rule is in the Internal Revenue Code and does not change by tax year. Last updated: October 2026.