Substantial Presence Test Explained: Are You a US Tax Resident?

For non-U.S. citizens spending significant time in the United States—such as digital nomads, extended tourists, or business travelers—understanding your U.S. tax status is crucial. The Internal Revenue Service (IRS) uses two primary methods to determine if you are a U.S. resident for tax purposes: the Green Card Test and the Substantial Presence Test (SPT). [1]

While the Green Card Test is straightforward (if you have a green card, you are a tax resident), the Substantial Presence Test is a more complex, formula-based calculation. Passing this test means the U.S. government considers you a tax resident, obligating you to pay U.S. taxes on your worldwide income, just like a U.S. citizen.

This guide will break down the Substantial Presence Test, explain how to calculate your days, and cover the important exceptions that might exempt you.

What is the Substantial Presence Test?

The Substantial Presence Test is a mathematical formula used by the IRS to determine if an individual has spent enough time in the United States to be considered a resident for tax purposes. You meet the test if you have been physically present in the U.S. for at least:

1. 31 days during the current year, AND
2. 183 days during the 3-year period that includes the current year and the 2 years immediately before that.

However, not all days are counted equally. The 183-day total is calculated using a weighted formula.

The 183-Day Formula

To determine if you meet the 183-day requirement, you must apply the following formula: [2]

• All days you were present in the current year
• + 1/3 of the days you were present in the first year before the current year
• + 1/6 of the days you were present in the second year before the current year

If the total from this calculation is 183 days or more (and you were present for at least 31 days in the current year), you are considered a U.S. tax resident.

Example Calculation

Let’s say you are a non-U.S. citizen and spent the following number of days in the United States over the last three years:

• 2026 (Current Year): 120 days
• 2025 (Previous Year): 150 days
• 2024 (Second Previous Year): 180 days

Here’s how you would apply the formula:

Year	Days in U.S.	Multiplier	Calculated Days
2026	120	1	120
2025	150	1/3	50
2024	180	1/6	30
Total			200 days

Since you were in the U.S. for more than 31 days in 2026 (120 days) and your three-year total is 200 days, you meet the Substantial Presence Test and would be considered a U.S. tax resident for 2026.

Which Days Count as a "Day of Presence"?

A "day of presence" is any day you are physically present in the United States at any time during the day. However, there are several exceptions. You should not count the following days: [3]

• Days you are in the U.S. for less than 24 hours while in transit between two foreign locations.
• Days you are unable to leave the U.S. because of a medical condition that developed while you were in the U.S.
• Days you are an "exempt individual."
• Days you are a regular commuter from a residence in Canada or Mexico.

Who is an "Exempt Individual"?

Certain individuals can exclude their days of presence in the U.S. for the purposes of the SPT. This is a critical exception for many international visitors. The main categories of exempt individuals are: [4]

• Students: Individuals on an "F," "J," "M," or "Q" visa who substantially comply with the requirements of their visa. Generally, a student can claim this exemption for up to 5 calendar years.
• Teachers or Trainees: Individuals on a "J" or "Q" visa who are not students and who substantially comply with their visa requirements. This exemption is typically available for 2 of any 6 prior calendar years.
• Government-Related Individuals: Employees of foreign governments or international organizations with a "A" or "G" visa.
• Professional Athletes: Athletes temporarily in the U.S. to compete in a charitable sports event.

The Closer Connection Exception

What if you meet the Substantial Presence Test but consider another country your home? The Closer Connection Exception may allow you to still be treated as a non-resident alien. To qualify for this exception, you must: [5]

1. Be present in the U.S. for fewer than 183 days during the current year.
2. Maintain a tax home in a foreign country during the year.
3. Have a closer connection to that foreign country than to the U.S.

To claim this exception, you must file Form 8840, Closer Connection Exception Statement for Aliens. The IRS will evaluate factors such as the location of your permanent home, family, personal belongings, and social/political/cultural affiliations.

Conclusion

The Substantial Presence Test is a nuanced but critical component of U.S. tax law for foreign nationals. Failing to correctly determine your status can lead to unexpected tax bills and penalties. It is essential to meticulously track your days in the United States and understand how the formula applies to you.

Using a tool like DayMap can help you monitor your days and stay below critical thresholds. If you believe you might meet the test or qualify for an exception, consulting with a U.S. tax professional is the best course of action to ensure you remain compliant.

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References

[1] IRS. (n.d.). Determining an individual's tax residency status. Internal Revenue Service. [2] IRS. (n.d.). Substantial Presence Test. Internal Revenue Service. [3] Freeman Law. (n.d.). The Substantial Presence Test | Tax Compliance. [4] University of California, Berkeley. (n.d.). Substantial Presence Test. Controller's Office. [5] IRS. (2025, July 15). Closer Connection Exception to the Substantial Presence Test.

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