US Tax Residency in 2026: Know Your Status Before the IRS Decides It

Last reviewed: November 2026 · Reviewed by Stéphane Gombauld, tax expert, technologist and digital nomad

You spend time in the US, or you hold a US passport while living elsewhere. The US rules look mechanical, but they hide traps: citizenship-based taxation, weighted days and state residency. After reading, you will know which status applies to you in 2026 and how to prove it.

United States tax residency rules in 2026: the key figures

Is this guide for you?

Read on if you…

• are a non-US citizen spending months at a time in the US;
• hold a green card but live mostly abroad;
• are a US citizen or dual national living outside the US.

Probably not your case if you…

• only visit the US for a few weeks a year as a tourist;
• want a step-by-step relocation plan: see our practical guide to obtaining US tax residency.

Who counts as a US tax resident?

Federal law sorts everyone into three groups. The definitions sit in section 7701(b) of the Internal Revenue Code (the US tax law).

Citizenship-based taxation

The US is one of very few countries that taxes its citizens wherever they live. If you hold a US passport, you file every year above the filing threshold. "Accidental Americans" (people born in the US who left as children) are caught too. Relief comes from the foreign earned income exclusion and the foreign tax credit, not from leaving.

The green card test

A green card holder is resident from the first day in the US as a permanent resident. Living abroad does not end it. Only formal abandonment (Form I-407) or a final revocation does. A treaty tie-breaker can make you non-resident for income tax, but that has exit tax consequences.

How does the substantial presence test work?

Counting the days

A day counts if you are physically in the US at any moment. You need two things in 2026:

1. at least 31 days of presence in 2026, and
2. at least 183 days using this formula: all 2026 days + one third of 2025 days + one sixth of 2024 days.

Example: 120 days each year gives 120 + 40 + 20 = 180. You stay non-resident. At 122 days a year, you hit 183 and pass.

Days that do not count

• Days in transit between two foreign points, under 24 hours.
• Days you could not leave because of a medical condition that arose in the US.
• Commuting days from Canada or Mexico, if you commute regularly.
• Days as an exempt individual: diplomats, students on F, J, M or Q visas (usually five calendar years), teachers and trainees on J or Q visas (usually two of the last six years).

The closer connection exception

If you pass the test but spent fewer than 183 days in the US in 2026, you can stay non-resident. You must keep a tax home in another country (your main place of business or work) and closer personal ties there. File Form 8840 with your return or by the due date. Miss it, and the exception is generally lost.

What happens in the year you arrive or leave?

Your residency timeline

• Before arrival: you are non-resident and taxed only on US-source income.
• Start date: the first day of presence in the year you pass the test, or your first day with a green card. Up to 10 days of earlier short visits can be ignored.
• Resident period: worldwide income, Form 1040, full deductions.
• End date: your last day of presence, if you then have a closer connection abroad for the rest of the year. Green card holders end on the date status is formally abandoned.
• After departure: non-resident again, filing Form 1040-NR if you still have US income.

The year of arrival or departure is usually a dual-status year. You cannot file jointly with a spouse unless you both elect to be resident for the whole year. You also cannot use the standard deduction in a dual-status year.

How do treaties and state rules change the picture?

Treaty tie-breakers

If another country also treats you as resident, the treaty tie-breaker decides. It looks at permanent home, centre of vital interests (basically where your life is: home, partner, kids, main business), habitual abode and nationality. You declare a treaty position on Form 8833. Most US treaties contain a "saving clause": the US still taxes its own citizens as if no treaty existed.

State residency is separate

Each state has its own test. Many use "domicile" (your permanent home) plus a day count. New York, for example, treats you as a statutory resident with a permanent place of abode and more than 183 days there. California looks at the closeness of your connections. You can be non-resident federally and still owe state tax, or the reverse.

For the full picture of federal and state taxes, see our US tax landscape overview.

Common mistakes (and what they cost)

• Counting only this year's days → You miss the weighted formula, become resident and owe tax on worldwide income.
• Thinking a green card "sleeps" while you live abroad → You remain a US tax resident with full filing duties until it is formally abandoned.
• Not filing Form 8840 or 8843 → You lose the exception or exemption and the days count against you.
• Forgetting state residency → A state like California or New York can tax your whole income for the year.
• Assuming a treaty frees US citizens → The saving clause keeps citizens fully taxable in the US.

Frequently asked questions

Can I be a US tax resident without a visa or green card?

Yes. The substantial presence test only counts days, not immigration status. A visitor on the Visa Waiver Program or a B-1/B-2 visa who stays long enough over three years can pass it. Immigration rules limit how long you can stay, but tax residency follows the calendar, not the visa stamp.

Do US citizens living abroad have to file a US tax return?

Yes, if their gross income is above the filing threshold, which is linked to the standard deduction. Living abroad gives an automatic two-month extension, to 15 June. Most expats owe little or nothing thanks to the foreign earned income exclusion and the foreign tax credit, but they must still file and report foreign accounts.

What is a dual-status tax year?

It is a year in which you are non-resident for part of the time and resident for the rest, typically when you arrive or leave. You file a return covering both periods, with Form 1040 and a 1040-NR statement, or the reverse. Special limits apply: no standard deduction and no joint filing without an election.

How do I prove a closer connection to another country?

Form 8840 asks about your permanent home, family location, personal belongings, bank accounts, driver's licence, voter registration and where you file taxes. You must have a tax home abroad for the whole year. Keep leases, utility bills and the foreign tax return as evidence in case the IRS asks.

Does a tax treaty stop the substantial presence test?

Not directly. You may still pass the test and be resident under US domestic law. The treaty tie-breaker then decides which country wins for income tax purposes. You claim it on Form 8833. Green card holders who do this for long enough can trigger expatriation rules, so check before you claim.

Are F-1 students tax residents of the US?

Usually not during their first five calendar years in the US. F-1 students are exempt individuals, so their days do not count for the substantial presence test. They must file Form 8843 each year. After five years, days start counting unless they show they do not intend to stay permanently.

Related guides

• Practical guide to obtaining US tax residency
• How to cease your US tax residency
• US tax incentives for expats and digital nomads
• US capital gains tax
• US tax landscape overview
• Tax residency rules in the United Kingdom
• All country tax guides

Sources

• IRS – Determining an individual's tax residency status
• IRS – Publication 519, US Tax Guide for Aliens
• IRS – Publication 54, Tax Guide for US Citizens and Resident Aliens Abroad
• IRS – United States income tax treaties A to Z
• US Code – Title 26 (Internal Revenue Code)
• OECD – Tax treaties

This guide is general information, not personalised tax advice. See how we research and review.