If you are not a U.S. citizen, you file as either a resident or a nonresident alien. Nonresident aliens use Form 1040-NR, which has different deadlines, deductions and credits from Form 1040.
This guide explains how to tell which one you are, who must file, the due dates, how income is taxed and which deductions and credits apply, using the IRS 2025 Instructions for Form 1040-NR.
The IRS says a non-citizen is generally a resident alien if they meet the green card test or the substantial presence test for 2025, and otherwise a nonresident alien who files Form 1040-NR. You meet the green card test if you were a lawful permanent resident of the United States at any time during 2025. You meet the substantial presence test if you were present in the United States at least 31 days during 2025 and at least 183 testing days over 2025, 2024 and 2023.
| Year | Days present | Multiplier | Testing days |
|---|---|---|---|
| 2025 | 120 | 1.000 | 120.00 |
| 2024 | 120 | 0.333 | 39.96 |
| 2023 | 120 | 0.167 | 20.04 |
| Total | 180.00 |
Our illustration: 120 days in each year gives 180 testing days, below 183, so this person is not a resident under this test. With 122 days in each year the total is exactly 183.000, which meets the test. The IRS lists exceptions for days that do not count, and a closer connection exception for some people who meet the test, claimed on Form 8840. Dual-resident taxpayers who are treaty residents of another country can file Form 1040-NR and attach Form 8833.
| If you... | Filing duty (IRS Table A) |
|---|---|
| Were a nonresident alien engaged in a U.S. trade or business in 2025 | File, even if you have no U.S.-trade-business income, no U.S. source income or your income is treaty-exempt |
| Were a nonresident alien not engaged in a U.S. trade or business and received Schedule NEC income that was not fully taxed at the source | File |
| Owe special taxes such as alternative minimum tax, additional tax on a qualified plan (including an IRA) or other tax-favored account, or household employment taxes | File |
Even if you do not have to file, the IRS says you should file if you are eligible to get back any federal income tax withheld. You need not file if you were a nonresident alien student, teacher or trainee temporarily present under an F, J, M or Q visa and have no income subject to tax under section 871, or if you were a student or business apprentice eligible under Article 21(2) of the U.S.-India tax treaty whose 2025 gross income was $15,750 or less if single ($31,500 for a qualifying surviving spouse). You also need not file as a partner in a U.S. partnership not engaged in a U.S. trade or business if your Schedule K-1 shows only income reportable on Schedule NEC lines 1 through 12, unless the tax withheld was wrong.
| Case | 2025 return due |
|---|---|
| Employee with wages subject to U.S. income tax withholding | April 15, 2026 |
| No wages subject to withholding | June 15, 2026 |
If the date falls on a weekend or legal holiday you file by the next business day. For a 2026 return the same rule gives April 15, 2027 or June 15, 2027; the 2026 instructions were not published as of 26 October 2026, so check them when released. A nonresident alien filing Form 1040-NR cannot use married filing jointly or head of household. If you are married, choose married filing separately even if you are not separated, subject to the exception in the instructions for some married people who live apart from their spouse. You can check Qualifying surviving spouse only if you were a resident of Canada, Mexico or South Korea, a U.S. national, or a student or business apprentice from India eligible under Article 21(2) of the treaty, and you were a resident alien or U.S. citizen in the year your spouse died. The 2025 form offers Single, Married filing separately, Qualifying surviving spouse, Estate and Trust boxes, and asks whether at any time during 2025 you received digital assets as a reward, award or payment, or sold or exchanged one. See our head of household guide for the status you cannot use.
You report income effectively connected with a U.S. trade or business on the main form and it is taxed at regular rates. U.S. income not effectively connected is taxed at 30% unless a treaty sets a lower rate, and you report it on Schedule NEC (Form 1040-NR); tax on it must be withheld at source at generally 30%. The 30% applies to amounts in gross income, such as fixed or periodic income, and 85% of U.S. social security benefits is taxable and treated as this kind of income. Capital gains from U.S. sources are taxable under this schedule only if you were in the United States at least 183 days during 2025. You complete the applicable items on Schedule OI (Form 1040-NR) and include it with your return; Schedule A (Form 1040-NR) is used only with Form 1040-NR. You may also need the numbered Schedules 1, 1-A, 2 and 3 (Form 1040); see our Schedule 1 guide and Schedule 3 guide.
Nonresident aliens generally cannot take the standard deduction. The exception in the instructions is students or business apprentices from India eligible under Article 21(2) of the treaty, who may take the standard deduction on line 12. Child tax credit, credit for other dependents, additional child tax credit and the premium tax credit for dependents are available in full only to residents of Canada and Mexico and to U.S. nationals, and to a limited extent to residents of India and South Korea; other nonresident aliens cannot claim them. For 2025 the maximum child tax credit is $2,200 per qualifying child of which $1,700 can be the refundable part. See our Schedule 8812 guide.
Next-year note: for tax years beginning in 2026, Rev. Proc. 2025-32 sets the standard deduction at $16,100 for single filers and married filing separately and $32,200 for surviving spouses, and keeps the maximum child tax credit at $2,200 with $1,700 refundable. The India treaty filing threshold above is the 2025 standard deduction ($15,750 single, $31,500 surviving spouse); we have not seen the 2026 instructions confirm how it will be set, so check them when published.
This guide covers the 2025 instructions used to file in 2026. Treaty terms vary by country, so read the treaty and Publication 519 before relying on a rate.
IRS: Instructions for Form 1040-NR, U.S. Nonresident Alien Income Tax Return, IRS: Form 1040-NR, IRS: Rev. Proc. 2025-32 (2026 inflation adjustments).