United States: The Substantial Presence Test

The Substantial Presence Test is the rule for counting days that the U.S. tax authority, the IRS, applies to a foreign national without a green card. It is met when two thresholds are met simultaneously: 31 days of presence in the United States in the year, and 183 weighted days over three years.

This page explains the formula and how to count the days. It does not cover the details of the green card test, how US residency affects your income tax, or the tax treaty between France and the United States.

The formula

The IRS publishes the rule on its "Substantial presence test" page (reviewed or updated on 03/14/2026). It is assessed per calendar year ("calendar year" in the IRS text).

The weighted total adds up to:

• all days of attendance in the current year, counted as 1; ;
• the days of the previous year, counted as one third; ;
• the days of the previous year, counted as one sixth.

The IRS provides an example in Publication 519: 120 days of presence each year equals 120 + 40 + 20 = 180 days. This is less than 183 days: the person is not a resident according to this test.

The pitfall of the formula: the last two years carry weight, even when the current year seems reasonable. Attendance of 120 days each year remains below the threshold, but 130 days each year exceeds it. The count is recalculated each calendar year.

This counts as a day of attendance

A day counts as being physically present in the country. The IRS website states: "You are treated as present in the US on any day you are physically present in the country, at any time during the day." For this test, US territories and US airspace are not considered part of the "United States.".

The days that don't count

The IRS excludes the following from the count:

• the days of regular travel between Canada or Mexico and the American workplace; ;
• days spent in the United States for less than 24 hours, in transit between two locations outside the country; ;
• crew days on a foreign ship; ;
• the days when you cannot leave the country because of a medical condition that developed while you are in the United States; ;
• the days of an "exempt individual".

«"Exempt individual" refers to a category of people defined by the IRS, for example, based on their visa status. This does not mean exempt from taxes.

Excluding days requires a formality: you must include Form 8843 with your tax return ("you must include Form 8843"), or send it to the designated address if you are not filing a return. If you do not file on time, these days cannot be excluded unless you provide clear and convincing evidence of reasonable steps taken to comply with the obligation.

Test completed: does that make you a resident?

Not necessarily. The IRS provides for exceptions, including the "closer connection" exception. This exists in two versions: a general exception and an exception specifically for foreign students.

According to Publication 519 (2025 edition), a person who completes the test can be treated as a non-resident if they meet three conditions:

1. It is present in the United States for less than 183 days a year; ;
2. She maintains a "tax home" in a foreign country during the year; ;
3. During the year, she has closer ties with the foreign country where she has her "tax home" than with the United States (the publication deals separately with the case of two foreign countries).

Form 8840 is used to claim this exception. The IRS describes it as follows on its March 30, 2026 page: "Use Form 8840 to claim the closer connection to a foreign country(ies) exception to the substantial presence test." Publication 519 specifies that a completed Form 8840 must be attached to the income tax return before the deadline for Form 1040-NR.

The exception is excluded if, during the year, you applied for or took steps to become a permanent resident, or if an application for adjustment of status was in progress.

There remains another option: the tax treaty. According to Publication 519, a dual resident claiming the benefits of a treaty files Form 1040-NR along with Form 8833. If the treaty designates them as a resident of a foreign country, they are treated as a non-resident for U.S. income tax purposes. According to the publication, a green card holder who invokes foreign residency under a treaty tie-breaker rule is also treated as a non-resident for tax purposes. The content of the Franco-American tax treaty is not discussed on this page.

The two residency tests

On its page "Determining an individual's tax residency status" (updated 02/11/2026), the IRS sets out the basic rule: a non-citizen is a non-resident unless they pass one of two tests, the green card test or the Substantial Presence Test. The page also lists choices that can change the result: the first-year election, a non-resident spouse treated as a resident, a closer connection to a foreign country, and tax treaties.

The year of arrival or departure, or a single year, can be partly residential and partly non-resident. The IRS then requires a dual-status tax return.

Substantial Presence Test: numerical example (fictitious profile)

Situation. Two fictitious French executives, A and B, each spend several weeks a year in the United States for work. We assume that the year 2026 is over and calculate their total.

Issue. Everyone believes they are sticking to "less than 183 days" and only counts the current year.

Strategy. The formula is applied: current year × 1, previous year × 1/3, previous year × 1/6.

• A: 90 days in 2026, 105 in 2025, 120 in 2024.
• B: 150 days in 2026, 120 in 2025, 120 in 2024.

Result. A reaches 90 + 35 + 20 = 145 weighted days: the test is not met. B reaches 150 + 40 + 20 = 210 weighted days, with 150 days in the year: the test is met. B remains below 183 days in 2026, which satisfies the first of the three conditions for the closer connection exception; the other two depend on its facts.

These profiles are fictitious. The calculation is indicative and does not reflect a person's actual status.

Substantial Presence Test: what changes depending on your case

• Your visa and your status : some days are deducted, others are not.
• Your green card, or a pending application : it rules out the exception of a closer link for the year in question.
• Your year of arrival or departure Dual status is possible.
• Your country of habitual residence : the tax treaty may change the result, upon filing of forms 1040-NR and 8833.
• Your supporting documents : excluded days and exceptions are demonstrated by forms submitted on time.

No results are promised.