What a Non-Resident Actually Files
A nonresident alien does not file the same return as a U.S. person, and the difference is not just the form number. Form 1040-NR is built around a split that has no equivalent on a resident return: U.S.-source income is sorted into one of two baskets, and each basket is taxed under a completely different method. Getting the sorting right determines whether a given dollar is taxed on a net basis at graduated rates or on a gross basis at a flat rate, and the two produce materially different results on identical income.
The two baskets
IRC §871 sets out the split. Income that is effectively connected with the conduct of a U.S. trade or business is taxed under IRC §871(b) the same way a U.S. person's business income is taxed: at the graduated rates in IRC §1, on a net basis, after allowable deductions. Income that is not effectively connected, and that falls within the statutory description of fixed or determinable annual or periodical income, commonly called FDAP income, is taxed under IRC §871(a) at a flat 30 percent rate on the gross amount, with no deductions against it, unless a tax treaty reduces that rate for the specific category of income involved.
IRC §864(c) defines what counts as effectively connected income, generally requiring both that the nonresident is engaged in a U.S. trade or business and that the income has the necessary connection to that business, tested through an asset-use standard and a business-activities standard depending on the type of income. A separate dossier on this site works through that classification question in depth; the point for filing purposes is that every dollar of U.S.-source income has to be sorted into one basket or the other before the return can be prepared, because the two baskets are reported in different places on the form and taxed by different mechanics.
| Feature | Effectively connected income (ECI) | FDAP income |
|---|---|---|
| Governing provision | IRC §871(b) | IRC §871(a) |
| Tax base | Net, after allowable deductions | Gross, no deductions |
| Rate | Graduated rates under IRC §1 | Flat 30 percent, or a lower treaty rate |
| Typical examples | Income from an active U.S. business, gain from certain U.S. real property dispositions treated as ECI under IRC §897 | U.S.-source interest, dividends, royalties, certain rents, and similar passive-type payments |
| Collection method | Generally reported and paid with the return, though withholding may apply on payments to foreign partners or under specific regimes | Generally collected up front through withholding by the payor under IRC §1441 and reported to the recipient on Form 1042-S |
Where each basket lands on Form 1040-NR
Form 1040-NR's main body reports effectively connected income and its associated deductions, computed and taxed in a structure that closely parallels a resident Form 1040: income items, adjustments, allowable deductions, and tax computed at graduated rates on the net result. FDAP income that is not effectively connected does not go on the main form at that graduated rate. It is reported instead on Schedule NEC, Tax on Income Not Effectively Connected With a U.S. Trade or Business, which lists income by category, such as interest, dividends, royalties, and other fixed or determinable income, applies the statutory 30 percent rate or the specific reduced treaty rate claimed for that category, and carries the resulting tax back to the main form as a separate line item added to the tax on the ECI basket.
A third component, Schedule OI, Other Information, does not report income at all. It reports the facts the IRS needs to confirm the nonresident filing position itself: the individual's country of residence for tax purposes, visa type and immigration status, dates of entry and exit, a day-count summary supporting the nonresident conclusion under the substantial presence test, and disclosure of any treaty article being claimed to reduce withholding or exempt specific income. A return that reports FDAP or ECI income but omits Schedule OI's supporting detail is incomplete, because the schedule is what documents why the taxpayer is filing as a nonresident in the first place rather than as a resident.
What deductions are actually available
IRC §873 limits the deductions a nonresident alien may claim to those connected with income effectively connected with a U.S. trade or business, with a short list of specific exceptions that apply regardless of connection: casualty and theft losses on property located in the United States under IRC §165, and charitable contributions to qualifying U.S. organizations under IRC §170. Deductions that a resident taxpayer takes for granted, such as those tied to non-business personal expenses unconnected to the U.S. business, are simply unavailable against FDAP income, because FDAP income is taxed on a gross basis by design and no deduction mechanism applies to it at all.
The standard deduction is generally unavailable to a nonresident alien under IRC §63(c)(6)(B). A narrow exception exists under specific treaty language, most notably a provision in the U.S.-India treaty that has been read to extend standard deduction treatment to certain Indian students and business apprentices; whether that or any other treaty-based exception applies to a specific filer is a treaty-interpretation question, not a general rule available to nonresidents broadly. Personal exemptions, which historically offset a fixed amount per taxpayer and dependent, were suspended by 2017 federal legislation and remain unavailable in computing the tax due, a change that affects resident and nonresident returns alike.
Credits available to residents, including the earned income tax credit, are generally unavailable to a nonresident filing a full-year Form 1040-NR. Certain credits tied to effectively connected business activity, and the foreign tax credit under IRC §901 to the extent it relates to income also taxed by a foreign country, may still be available depending on the specific facts.
The filing deadline depends on whether wages were withheld
Form 1040-NR does not carry a single filing deadline for every nonresident. IRC §6072(c) sets the due date at April 15 following the close of the tax year for a nonresident alien who has wages subject to U.S. income tax withholding, the same deadline that applies to a resident return. A nonresident alien who does not have wages subject to withholding, typically someone whose only U.S. income is FDAP income already collected through withholding at the source, or business income not connected to employment, has until June 15 following the close of the tax year to file. This distinction is easy to miss because most tax calendars default to April 15, and a nonresident who assumes the June date applies without confirming the absence of withheld wages can end up filing late without realizing it.
A worked example: the same source, two different results
Consider a nonresident alien who owns a rental property in the United States. If the individual takes no affirmative steps and simply collects rent, that rental income is generally treated as FDAP income, U.S.-source, fixed and determinable, taxed at a flat 30 percent on the gross rent received, with the tenant or property manager withholding at that rate under IRC §1441 before the owner ever sees the funds. No deduction is allowed against that 30 percent tax for mortgage interest, property tax, depreciation, or repairs, because FDAP income is a gross-basis tax by design.
IRC §871(d) offers a different path: a nonresident alien who owns U.S. real property can elect to treat income from that property as effectively connected with a U.S. trade or business, even where the activity alone might not otherwise rise to that level. Once the election is made, the same rental income moves into the ECI basket, reported on the main body of Form 1040-NR rather than Schedule NEC, taxed at graduated rates on the net amount after depreciation, mortgage interest, property tax, and other ordinary rental deductions under IRC §873. The election is binding for future years unless revoked with IRS consent, and whether it produces a better or worse result depends entirely on the specific numbers, particularly how much the allowable deductions offset the gross rent. The mechanism illustrates why the ECI and FDAP classification is not just a reporting formality: identical income, differently classified, produces a materially different computation.
Extensions and estimated tax follow the same split-deadline logic
A nonresident alien can request an extension of time to file using Form 4868, the same form a resident uses, which generally extends the filing deadline by six months from whichever due date applies, April 15 or June 15. An extension of time to file is not an extension of time to pay; any tax reasonably estimated to be due should be paid with the extension request to limit interest and the failure-to-pay penalty under IRC §6651(a)(2), which continues to run from the original due date regardless of the extension.
IRC §6654 applies the estimated tax underpayment rules to a nonresident alien with a filing obligation the same as it applies to a resident, based on the tax shown on the return after withholding is taken into account. Because FDAP income is generally fully withheld upon payment, estimated tax exposure on a Form 1040-NR usually arises from the ECI basket, where no withholding mechanism automatically covers the graduated-rate tax the way §1441 withholding covers FDAP income at the flat rate.
State income tax is a separate analysis
Form 1040-NR is a federal return, and filing it settles nothing about state income tax. A nonresident with U.S.-source income sourced to a state that imposes an income tax may have a separate state filing obligation, governed by that state's own nonresident sourcing and nexus rules rather than by IRC §871. Some states start from federal effectively connected income as a baseline and diverge from there, and some tax categories of income differently than the federal ECI and FDAP split does. State exposure has to be checked state by state and is not resolved by anything on the federal Form 1040-NR itself.
What happens when no return is filed at all
IRC §874(a) attaches a specific consequence to not filing that has no direct parallel for a resident taxpayer: deductions and credits against effectively connected income are allowed only if a true and accurate return is filed, and if no return is filed within the time the regulations specify, the IRS can compute the tax on the gross amount of the income without allowing any offsetting deductions at all. In practice this means a nonresident who never files, and whose income is later identified through third-party reporting such as a Form 1042-S, a Form 8288-A withholding record on a real property sale, or a Form 1099, can be assessed tax on the gross income with no deductions recognized, even where deductions would clearly have been allowable had a timely return been filed.
Beyond that specific deduction-denial rule, ordinary failure-to-file and failure-to-pay penalties under IRC §6651 apply, computed from the due date that actually governed the return, April 15 or June 15 depending on the withholding facts above. And because IRC §6501(c)(3) provides that the assessment statute of limitations does not begin to run at all for a year in which no return was filed, a nonresident who never files a required Form 1040-NR remains exposed to assessment for that year indefinitely, with no three-year clock ever starting to close it out.
Next steps
Preparing a Form 1040-NR starts with sorting every item of U.S.-source income into the ECI or FDAP basket before anything else is computed, since that sorting decides which schedule the income lands on and which rate structure applies to it. A separate dossier on this site works through the ECI classification question itself in more depth. Confirming which April or June deadline applies, and filing even where no tax is ultimately due, protects both the deductions available under IRC §873 and §874(a) and the statute of limitations that only begins to run once a return is on file.
This is general information about how Form 1040-NR and the underlying ECI and FDAP rules operate as of the date written. It is not advice on any individual's filing position, and classifying a specific item of income belongs with a qualified preparer.