The Substantial Presence Test: How the IRS Determines Your U.S. Tax Residency

When a non-U.S. citizen spends time in the United States, one of the most consequential tax questions is whether that person is a Resident Alien or a Nonresident Alien for federal income-tax purposes. The answer determines which tax return to file, which income to report, and whether treaty benefits or special withholding rules apply.

The IRS's primary tool for making that determination is the Substantial Presence Test (SPT), codified at IRC § 7701(b).

The Substantial Presence Test is a mechanical, day-counting formula. It does not ask where you intend to live, where your family is, or where you consider home. It asks one question: how many days were you physically present in the United States over the past three calendar years?

Passing the test generally means you are treated as a Resident Alien and taxed similarly to a U.S. citizen — on your worldwide income, using Form 1040.

Failing the test generally means you remain a Nonresident Alien — taxed on U.S.-source income and certain effectively connected income, using Form 1040-NR.

Note that the Substantial Presence Test is not the only path to resident-alien status. A non-U.S. citizen who holds a green card satisfies the Green Card Test and is a resident alien regardless of how many days were spent in the United States.

You meet the Substantial Presence Test if both of the following conditions are true:

1. You were physically present in the United States for at least 31 days during the current calendar year, and
2. The weighted total of your U.S. days over the current year and the two preceding years equals 183 days or more.

Both conditions must be satisfied. If you were present for 31 or more days this year but your weighted total falls below 183, you do not pass. If your weighted total exceeds 183 but you were present for fewer than 31 days this year, you also do not pass.

The IRS does not count all three years equally. The formula weights recent presence more heavily:

Formula:

If the weighted total is 183 or more, and you meet the 31-day minimum in the current year, you generally satisfy the Substantial Presence Test.

• Current year: 150 days (exceeds the 31-day minimum)
• Weighted total: 200 days (exceeds 183)

Result: Resident Alien for 2026.

• Current year: 90 days (exceeds 31)
• Weighted total: 135 days (below 183)

Result: Nonresident Alien for 2026.

Even though this individual was present for 270 days across three years, the weighted formula produces a total below the threshold.

Not every day of physical presence in the United States is automatically counted toward the Substantial Presence Test. Certain days may be excluded, including:

• Days as a qualifying exempt individual — which includes certain F-1, J-1, M-1, and Q visa holders (discussed in detail below)
• Days when the individual was unable to leave the United States because of a medical condition that arose while present in the country
• Days as a foreign government-related individual (A or G visa holders performing official duties) who meets the applicable statutory requirements
• Days as a teacher or trainee in J or Q status who meets the specific statutory requirements and has not been exempt for more than two of the preceding six years

The exclusion for medical inability to leave applies only when the condition arose while the person was already in the United States and prevented departure — it does not apply to a person who traveled to the United States specifically to receive medical treatment.

This is where many international students — including student-athletes — are surprised.

Students temporarily present in the United States under F-1, J-1, M-1, or Q visas may qualify as "exempt individuals" for purposes of counting days under the Substantial Presence Test.

The word exempt here is frequently misunderstood. It does not mean exempt from U.S. income tax. It means that qualifying days of physical presence are not counted toward the Substantial Presence Test calculation.

For F-1 students, the first five calendar years in F-1 status are generally excluded from the Substantial Presence Test day count, provided the student qualifies as an exempt individual during those years.

This means an F-1 student can be physically present in the United States for the entire calendar year — all 365 days — and those days will generally not push the student toward resident-alien status during the first five calendar years.

Maria arrives from Spain on an F-1 visa in August 2024 and enrolls at a U.S. university to compete in athletics.

During these first five calendar years, Maria is generally treated as an exempt individual for the Substantial Presence Test. Even though she is physically present for the entire year in 2025 through 2028, those days are generally excluded from the formula.

Beginning with the sixth calendar year (2029 in Maria's case, assuming no other exception applies), she will generally start counting her days toward the Substantial Presence Test. If she remains in the United States, she may satisfy the test and become a Resident Alien at that point.

An F-1 student claiming the exempt-individual exclusion is generally required to file Form 8843 — Statement for Exempt Individuals and Individuals with a Medical Condition — for each year the exclusion is claimed. Form 8843 is an informational form, not a tax return, and it is filed even when the student has no U.S. income and no other filing obligation.

Failing to file Form 8843 does not automatically make the days countable, but it can create compliance issues and may affect the ability to claim the exclusion if the IRS later questions the student's status.

J-1 exchange visitors in student status are generally treated as exempt individuals for two calendar years out of any six-year period. J-1 teachers and trainees may be exempt for two years out of any six-year period under a separate rule. The specific limits depend on the J-1 category and the applicable statutory requirements.

If you satisfy the Substantial Presence Test, you are generally a Resident Alien for the calendar year and typically:

• File Form 1040
• Report worldwide income, including income earned in your home country, foreign bank interest, foreign business income, and foreign endorsement or NIL income
• May qualify for the standard deduction if otherwise eligible
• May need to report foreign financial accounts on FinCEN Form 114 (FBAR) if aggregate balances exceed $10,000
• May need to report specified foreign financial assets on Form 8938 if applicable thresholds are met
• May be entitled to a foreign tax credit for taxes paid to another country on the same income

If you do not satisfy the Substantial Presence Test and do not hold a green card, you are generally a Nonresident Alien for the calendar year and typically:

• File Form 1040-NR
• Report only U.S.-source income and income effectively connected with a U.S. trade or business
• Are generally not required to report foreign-source income that is not effectively connected with a U.S. trade or business
• May be eligible for reduced withholding rates or exemptions under an applicable income-tax treaty
• Are generally not entitled to the standard deduction (with limited exceptions, such as for certain residents of Canada, Mexico, South Korea, and India under treaty provisions)

An international student-athlete earning NIL income, athletic compensation, or endorsement income must determine tax residency every year — not once at arrival.

During the first five calendar years in qualifying F-1 status, most international student-athletes will remain Nonresident Aliens. That means:

• Reporting only U.S.-source income on Form 1040-NR
• Potentially qualifying for treaty benefits on certain income
• Not being required to report foreign bank accounts or foreign income on a U.S. return (subject to exceptions)

Once the F-1 exemption period ends and the student begins counting days, the analysis changes. A student who has been in the United States for several years and continues to be present for most of the year may satisfy the Substantial Presence Test and become a Resident Alien — triggering worldwide income reporting, FBAR obligations, and a different set of withholding rules.

The most common mistake is assuming that F-1 status permanently prevents resident-alien classification. It does not. It delays the day count for a defined period. After that period, the ordinary Substantial Presence Test applies.

Tax residency should be determined annually, with a careful count of qualifying and excluded days, before filing any U.S. tax return.

• IRC § 7701(b) — Definitions of resident alien and nonresident alien; Substantial Presence Test
• Treas. Reg. § 301.7701(b)-1 — Resident alien defined
• Treas. Reg. § 301.7701(b)-3 — Days of presence in the United States; exempt individuals
• Form 8843 — Statement for Exempt Individuals and Individuals with a Medical Condition
• Form 1040-NR — U.S. Nonresident Alien Income Tax Return
• IRS Publication 519 — U.S. Tax Guide for Aliens

This article provides general educational information and does not constitute individualized tax, legal, or immigration advice. Tax residency determinations depend on specific facts including visa classification, days of presence, treaty positions, and other circumstances. Consult a qualified tax professional before filing any U.S. tax return or making residency determinations.