US Taxes for Non-Residents — Filed Correctly, Without the Guesswork

Who Is a Non-Resident for US Tax Purposes?

For US tax purposes, a non-resident alien is a foreign person who meets neither the Green Card Test nor the Substantial Presence Test. Unlike US citizens and residents — who are taxed on their worldwide income — non-residents are taxed only on income that is sourced in the United States. This is a fundamental distinction: a non-resident's foreign salary, foreign investments, and foreign business profits are generally outside the US tax net. What matters is whether income is US-source and how it is classified. Determining your status correctly is the first and most important step, because it dictates which form you file and what the US can tax.

Residency — The Substantial Presence Test

Because residency drives everything, the IRS uses an objective day-count formula — the Substantial Presence Test — to decide whether a foreign individual is taxed as a resident. The test looks at how much time you physically spend in the US across a three-year window, with special weighting for prior years. Certain visa categories are treated differently, and an exception exists for people with a closer connection to another country.

How the Day-Count Works

You meet the Substantial Presence Test if you are present in the US at least 31 days in the current year and 183 days over a weighted three-year period. The weighting counts all of the current year's days, one-third of last year's days, and one-sixth of the days from the year before that. For example, someone spending several months in the US each year can become a resident for tax even without a green card. Because the math is precise, accurate day-counting is essential.

Exempt Individuals & Closer Connection

Some people are "exempt individuals" whose US days don't count toward the test — most commonly students on F or J visas (for a number of years) and certain teachers and trainees. Even if you would otherwise meet the day count, the closer-connection exception can preserve non-resident status if you maintain a tax home and stronger ties in another country and file the right statement. These rules are nuanced and fact-specific, so they should be reviewed carefully before assuming a status.

US-Source Income — FDAP vs. ECI

Once status is settled, the next question is how your US income is classified, because non-residents are taxed under two very different regimes. The classification — FDAP or ECI — determines the rate, whether deductions are allowed, and how the income is reported.

FDAP Income (30% Withholding)

FDAP stands for Fixed, Determinable, Annual, or Periodical income — passive income such as dividends, interest, rents, and royalties. By default, FDAP income is taxed at a flat 30% rate withheld at the source on the gross amount, with no deductions. A tax treaty can reduce or eliminate this rate. FDAP income is reported to you and the IRS on Form 1042-S, and filing a return is often how over-withheld amounts are recovered.

Effectively Connected Income (ECI)

ECI is income effectively connected with a US trade or business — for example, profits from operating a business in the US or, in many cases, partnership income. Unlike FDAP, ECI is taxed at the same graduated rates that apply to US residents, but on a net basis, meaning related deductions are allowed. This often produces a lower effective tax than flat FDAP withholding. ECI is reported on Form 1040-NR with the appropriate schedules.

Tax Treaties — Reducing US Withholding

The United States has income tax treaties with more than 60 countries, and these treaties are one of the most powerful tools available to non-residents. A treaty can reduce the default 30% withholding on dividends, interest, or royalties — sometimes to 15%, 10%, or zero — and may exempt certain income such as scholarships or short-term wages. To claim a reduced rate at the source, you typically provide a Form W-8BEN to the payer. When you take a treaty-based position on your return, it is generally disclosed on Form 8833. Claiming the right treaty benefit is frequently the difference between over-paying and paying the correct amount.

ITIN — The Taxpayer ID for Non-Residents

To file a US return or claim a treaty benefit, you need a US taxpayer identification number. If you are not eligible for a Social Security Number, you must obtain an Individual Taxpayer Identification Number (ITIN) by filing Form W-7, usually together with your tax return and proof of identity. An ITIN is used only for tax purposes — it does not grant work authorization or immigration status. Common pitfalls include sending improper identity documentation and missing the link between the ITIN application and the return it supports. We prepare and submit the W-7 end to end to avoid delays.

US Real Estate — Rental Income and FIRPTA

US real estate is one of the most common reasons non-residents encounter US tax — and one of the most misunderstood. The rules differ sharply depending on whether you are renting the property or selling it.

Renting Out US Property

By default, gross rental income paid to a non-resident is subject to 30% withholding with no deductions — a harsh result. However, you can make a §871(d) election to treat the rental activity as effectively connected income, which lets you be taxed on net rental income (after expenses such as mortgage interest, property tax, repairs, and depreciation) at graduated rates. This is reported on Schedule E with Form 1040-NR and usually produces a much better outcome for landlords.

Selling US Property (FIRPTA)

When a non-resident sells US real property, FIRPTA generally requires the buyer to withhold 15% of the gross sales price — not the gain — and remit it to the IRS, using Forms 8288 and 8288-A. Because this often far exceeds the actual tax due, you can apply for a withholding certificate (Form 8288-B) to reduce the amount withheld up front. Either way, the withholding is reconciled against your actual tax when you file your return, and any excess is refunded. Planning ahead around a sale can free up significant cash.

Investment Income — Dividends, Interest, and Capital Gains

For foreign investors, the treatment of US investment income follows a few clear patterns. US dividends are generally subject to 30% withholding, frequently reduced by treaty. Much US-source interest qualifies for the "portfolio interest exemption" and can be received free of US withholding. Importantly, non-residents are generally not subject to US tax on capital gains from selling securities — a major advantage — though there are exceptions, including being present 183 days or more in the year and gains that are effectively connected to a US business. Gains from US real property are the key exception, taxed under FIRPTA.

International Students & Scholars

Students and scholars on F and J visas are often "exempt individuals," meaning their days in the US don't count toward the Substantial Presence Test for a set number of years — so they typically remain non-residents and file Form 1040-NR. Even with little or no income, many must file Form 8843 to document their exempt status. Country-specific treaty provisions frequently exempt a portion of scholarship income or wages from US tax, but the exemption must be claimed correctly. Getting these filings right early prevents problems with future visa or residency applications.

Filing Deadlines for Non-Residents

Deadlines for non-residents depend on whether you received US wages subject to withholding. If you did, your Form 1040-NR is generally due April 15; if you did not, the deadline is June 15. Extensions to October 15 are available on request, but interest still accrues on any unpaid tax from the original due date. The representative calendar below shows the typical dates:

Deadlines depend on your income and situation — we confirm the exact calendar for every client.

Common Mistakes

The most expensive non-resident mistakes are usually avoidable. Many people never file a return to recover tax that was over-withheld on FDAP income, effectively leaving money with the IRS. Others miss treaty benefits they were entitled to, or misjudge their residency status and file the wrong form entirely. Sellers of US property frequently overlook FIRPTA until 15% is withheld at closing. Finally, using consumer tax software that isn't built for Form 1040-NR — or a generalist preparer unfamiliar with cross-border rules — often leads to errors that cost far more than professional help would have.

Why Work With a Non-Resident Tax CPA

Non-resident US tax sits at the intersection of residency rules, income sourcing, multiple forms, and treaty nuance — areas where a single wrong assumption is costly. A dedicated CPA models your options, determines your status, classifies your income correctly, and files every required form — from 1040-NR to W-7, W-8BEN, 8833, and the FIRPTA forms. Just as importantly, the right advisor claims the treaty benefits you're owed, works to recover over-withheld tax, and can represent you before the IRS if questions arise. For foreign persons with US income, that expertise typically pays for itself in lower tax, recovered withholding, and peace of mind.