How to File Nonresident Taxes in the United States

A U.S. paycheck, rental property, consulting contract, or investment account can create a filing obligation even when you do not live in the United States. Knowing how to file nonresident taxes starts with one question: are you a nonresident alien for U.S. federal tax purposes? The answer determines which return to use, what income to report, which deductions are available, and whether a tax treaty can reduce your liability.

For Canadian residents and other international taxpayers, U.S. nonresident tax filing is often more complicated than simply reporting income on a standard tax return. The rules distinguish between the type of income earned, the number of days spent in the United States, and whether you conducted a U.S. trade or business. Filing the wrong form or treating withheld tax as final when it is not can result in missed refunds, penalties, or duplicate taxation.

Confirm Your U.S. Tax Residency First

A person is generally a U.S. tax resident for federal income tax purposes if they are a U.S. citizen, green card holder, or meet the substantial presence test. If none of those applies, you will usually be treated as a nonresident alien.

The substantial presence test is based on days physically present in the United States. You may meet the test if you were present for at least 31 days during the current year and 183 days under a three-year calculation. That calculation counts all days in the current year, one-third of the days in the prior year, and one-sixth of the days in the second prior year.

Several exceptions can apply. Certain students, teachers, trainees, commuters from Canada or Mexico, and people unable to leave the United States because of a medical condition may exclude days. A person who meets the day-count test may also qualify for the closer connection exception in limited circumstances. Tax residency is not always the same as immigration status, permanent residence in another country, or where you consider home to be.

A Canadian resident can also be considered a resident of both Canada and the United States under domestic rules. In that situation, the Canada-U.S. tax treaty tie-breaker rules may determine treaty residence. This is a technical area that should be reviewed before filing, especially where employment income, a business, real estate, or significant investments are involved.

How to File Nonresident Taxes With Form 1040-NR

Most nonresident aliens who must file a U.S. federal income tax return use Form 1040-NR, U.S. Nonresident Alien Income Tax Return. This form is different from Form 1040, which is generally used by U.S. citizens and resident aliens.

You may need to file Form 1040-NR if you had income effectively connected with a U.S. trade or business, such as U.S. employment income, self-employment income attributable to U.S. business activities, or income from operating a business in the country. You may also need to file if you received certain U.S.-source income subject to withholding and want to claim a refund of overwithheld tax.

For example, a Canadian consultant who performs services in the United States may have U.S. business income. A Canadian investor who sells U.S. real property will usually have a filing requirement because of the U.S. withholding rules that apply to foreign sellers. A student who earns wages from a U.S. employer may need to file a return even if federal tax was withheld from every paycheck.

Not every nonresident must file. If you had only certain fixed or periodic income, such as interest, dividends, royalties, or pensions, and the correct amount of tax was withheld at source, a federal return may not be required. However, filing can still be beneficial if you are entitled to a refund, a lower treaty rate, or deductions connected to qualifying income.

Understand the Two Main Types of U.S. Income

Nonresident tax reporting depends heavily on whether income is effectively connected income or fixed, determinable, annual, or periodic income, often called FDAP income.

Effectively connected income, or ECI, is generally income connected to a U.S. trade or business. It is reported on Form 1040-NR and taxed at graduated rates after eligible deductions. Wages for work performed in the United States are a common example. Business income may also be ECI, depending on the facts.

FDAP income generally includes passive U.S.-source income, such as dividends, royalties, pension payments, and some interest. It is typically subject to a 30% gross withholding tax unless a tax treaty provides a lower rate. Since the tax is imposed on gross income, expenses are not normally deductible against FDAP income.

The classification is consequential. A withholding slip showing tax deducted does not, by itself, establish that no return is required. Review the nature of the income, where the services were performed, the withholding rate, and any treaty position before deciding.

Gather the Records Before Preparing Your Return

Accurate filing starts with complete documentation. U.S. payers commonly issue Form W-2 for employee wages and Form 1042-S for income paid to foreign persons. Independent contractors may receive Form 1099-NEC, although the absence of a form does not eliminate a reporting obligation.

Collect records for every U.S. income source, including brokerage statements, partnership information, real estate closing documents, expense receipts, travel records, and prior-year returns. If you are claiming a treaty benefit, retain documents supporting your residence in the treaty country and your eligibility for the specific treaty article.

Your passport and U.S. entry records matter as well. They support the day count used to determine residency under the substantial presence test. For cross-border employees, maintain a calendar showing workdays performed in the United States versus Canada. The location where services were physically performed can be more relevant than the location of the employer or the bank account receiving payment.

Claim Tax Treaty Benefits Carefully

The United States has income tax treaties with many countries, including Canada. A treaty may reduce withholding on dividends, interest, royalties, pensions, or other income. It may also exempt certain employment or business income when specific conditions are met.

Treaty benefits are not automatic. The applicable article, limitation, residency status, and supporting facts must all align. In some cases, a payer can apply a reduced withholding rate in advance after receiving the appropriate documentation. In other cases, the taxpayer must file Form 1040-NR to claim a refund after tax was withheld.

Do not assume a treaty eliminates U.S. filing. A treaty exemption can still require disclosure on the return, and some treaty positions require additional reporting. Canadian taxpayers should also consider the Canadian tax return. U.S. tax paid may be eligible for a foreign tax credit in Canada, but the timing and income classification must be coordinated to avoid losing relief in one country.

Do Not Overlook State Tax Returns

Federal nonresident status does not settle your state tax obligations. Many states require a nonresident return if you earned wages in the state, operated a business there, owned rental property, sold real estate, or received other state-source income.

State rules vary widely. Some states use different filing thresholds, residency tests, and sourcing rules than the federal government. States also are not required to follow the Canada-U.S. tax treaty. A treaty benefit that reduces federal tax may not reduce state income tax.

This issue is especially relevant for remote workers, contractors, professional athletes, and business owners who worked in multiple states. Allocate income based on the applicable state rules rather than assuming that tax withheld by an employer is correct.

File by the Correct Deadline and Pay What You Owe

The normal deadline for a Form 1040-NR is generally April 15 when you received wages subject to U.S. withholding. If you did not receive such wages, the deadline is generally June 15. An extension can provide additional time to file, but it does not extend the time to pay tax due.

If you need more time, file the appropriate extension request by the original due date and make a reasonable payment toward any expected balance. Late filing and late payment penalties can apply separately. If you expect a refund, filing late may not create a penalty, but waiting can delay recovery of overwithheld tax.

Nonresident returns can sometimes be filed electronically, but eligibility depends on the form, software, attachments, and taxpayer identification number. Some treaty disclosures, first-time ITIN applications, and complex filings may require paper filing or professional preparation.

Avoid the Errors That Create Costly Follow-Up

The most common nonresident filing errors are predictable: using Form 1040 instead of Form 1040-NR, counting U.S. presence days incorrectly, reporting worldwide income when only U.S.-source income is required, or failing to report income because tax was withheld.

Other frequent problems include claiming deductions unavailable to nonresidents, overlooking a state return, and applying a treaty article without meeting its conditions. Rental real estate and U.S. property sales deserve particular care because elections, withholding rules, depreciation, and capital gain reporting can materially change the result.

A cross-border return should be prepared as one coordinated tax position, not as separate U.S. and Canadian filings completed in isolation. BOMCAS Canada assists Canadian residents and cross-border taxpayers with U.S.-Canada tax reporting, nonresident returns, and related compliance planning.

Before filing, compare your income documents to your travel records, confirm your residency status, and review whether treaty or state rules change the result. That final review is often where a preventable filing error becomes a properly documented tax position.