Filing Your Return: Form 1040 or 1040-NR, and State Taxes

Every spring, visa holders face a question most Americans never think about: which return do I file? The answer follows from your tax status, and getting it wrong is the most common filing error newcomers make. This chapter matches each status to its form, lists the deadlines, explains what a nonresident return allows and what a resident must also report about accounts abroad, and covers state income tax, which follows rules of its own.

Which federal form

Your status for the year (chapters 1 to 3) decides the form:

• Resident alien all year: Form 1040, exactly as a citizen files, reporting worldwide income.
• Nonresident alien all year: Form 1040-NR. Attach Form 8843 if you were an exempt individual, and Form 8840 if you claim a closer connection.
• Dual-status year: if you are a resident on December 31, Form 1040 marked "Dual-Status Return" with a statement (which can be a Form 1040-NR) for the nonresident part of the year; if you are a nonresident on December 31, the reverse.
• No income at all, but an exempt individual (for example an F-1 student or an F-2 spouse with no job): no return, but Form 8843 on its own.

A word on software. Much consumer tax software prepares only Form 1040, and a nonresident who files a 1040 with the standard deduction has filed the wrong return. Universities often arrange nonresident tax software for international students; ask your international office. If you filed the wrong form in an earlier year, correcting it with an amended return is usually better than leaving it.

Deadlines

For a calendar-year filer, Publication 519 sets these dates:

• Resident alien on December 31: April 15.
• Nonresident with wages subject to US withholding: April 15.
• Nonresident with no wages subject to withholding: June 15. This is also the date for a stand-alone Form 8843 from someone in this group.
• Extensions: Form 4868 extends the time to file to October 15 (or December 15 when the regular date is June 15). It does not extend the time to pay.

When a date falls on a weekend or legal holiday, the deadline moves to the next business day.

What a nonresident return allows

A Form 1040-NR splits income into two kinds:

• Effectively connected income, mainly wages for work in the US, taxed at the graduated rates;
• Other US-source income, such as dividends, taxed at a flat 30% or a lower treaty rate, on its own schedule.

Against effectively connected income a nonresident can claim some itemized deductions but not the standard deduction (again, except students and business apprentices covered by Article 21(2) of the US–India treaty). The main ones are state and local income taxes paid on that income, up to the cap set in the Schedule A instructions for Form 1040-NR, and certain charitable gifts to US organizations. Legislation in 2025 raised that cap and added a reduction above a high income level. The 2025 Form 1040-NR instructions carry the new limit, while the 2025 edition of Publication 519 still prints the old one, so take the figure from the current Form 1040-NR instructions.

Filing status is limited. A married nonresident generally uses the married filing separately rates; residents of Canada, Mexico and South Korea, and US nationals, may file as single if they lived apart from their spouse for the last six months of the year. A joint return is possible only through the elections in chapter 3. Dependents can be claimed only by residents of Canada, Mexico and South Korea, US nationals, and students and apprentices from India under Article 21(2). Treaty benefits are claimed on the return, with the article cited.

What a resident return adds: accounts abroad

Becoming a resident alien brings the reporting duties of a citizen. Two matter to almost every newcomer with a bank or investment account back home:

• FBAR (FinCEN Form 114). Required if the combined value of your foreign financial accounts was more than $10,000 at any time in the year. It is filed online with FinCEN, not with your tax return, due April 15 with an automatic extension to October 15.
• Form 8938. Attached to your tax return if your specified foreign financial assets are over the threshold for your filing status. For an unmarried person living in the US, that is more than $50,000 on the last day of the year or more than $75,000 at any time.

The two are separate obligations, and filing one does not satisfy the other. The FBAR and Form 8938 threshold checker tells you which apply. Interest, dividends and gains on those accounts are also taxable on your US return once you are a resident, with a foreign tax credit for tax paid abroad. Mutual funds bought abroad can fall under the PFIC rules, which Volume 2 covers.

When a joint return is worth checking

For a resident whose spouse also becomes a resident, or who elects to treat a nonresident spouse as a resident, filing jointly is often the larger saving of the year:

On $120,000 of wages, a joint return leaves federal income tax of $10,040. The same salary on single brackets, which at this income match the married filing separately brackets and deduction, owes $17,570. The catch is the one from chapter 3: the spouse's worldwide income joins the return. The nonresident spouse joint filing calculator runs both sides with your numbers.

State income tax: a separate set of rules

Federal tax status does not carry over to your state. Each state decides who its residents are, usually by where you live and how many days you spend there, and it can tax a federal nonresident alien who lives there as a full resident. A few points hold almost everywhere:

• You may file in more than one state. Moving between states during the year usually means part-year resident returns in both, and working in one state while living in another can mean a nonresident state return as well.
• States choose for themselves whether to follow federal tax treaties. A treaty exemption on your federal return may or may not apply on your state return; check the state's own instructions.
• Some states have no tax on wages, and rates elsewhere vary widely. The state income tax comparison shows the 2026 figures for your salary.
• Withholding needs its own form. Most income-tax states have their own withholding certificate; fill it in when you start a job or move.