Do I Need to File a US Tax Return? A Guide for Non-Residents with US Income

In short: For most non-residents, the payer has already held back 30% of the gross payment before it reaches you. That withholding is a default, not a final tax bill.

If you are not a US citizen or resident but you earn money from US sources, dividends, rent, royalties, capital gains, or fees for work done in the United States, the IRS has a claim on part of it. In most cases the payer withholds 30% of the gross amount before you see a cent. That 30% is not a settlement of what you owe. It is the rate the IRS applies when it knows nothing else about you, and it very often takes more than your real liability.

Filing is frequently the only route to a lower bill, a treaty rate, or a refund of tax that should never have left your hands.

The 30% default: how US withholding works for non-residents

Under IRC §§ 1441–1442, anyone paying US-source FDAP income to a foreign person must withhold 30% of the gross amount.

Under IRC §§ 1441–1442, anyone paying US-source FDAP income to a foreign person must withhold 30% of the gross amount. This covers dividends, interest, rents, royalties, compensation, and similar categories. The withholding agent, usually a broker, bank, or tenant, sends that money to the IRS on your behalf, so you receive the payment already reduced.

The 30% rate is a blunt instrument. It ignores any deductions you might claim, any treaty reduction your country has negotiated, and even the possibility that the income is not US-taxable at all once the right forms are filed. Absent a filing, the IRS simply keeps whatever was withheld.

When you must file Form 1040-NR

Form 1040-NR is the federal income tax return for non-resident aliens, and filing it is required in several distinct situations.

Form 1040-NR is the federal income tax return for non-resident aliens, and filing it is required in several distinct situations. You must file when you have US-source income effectively connected with a US trade or business (ECI), when you want a refund of over-withheld tax, or when you are claiming a treaty benefit to reduce or remove US tax on a category of income.

Even if your only US income is FDAP already subject to withholding, filing can still pay. A treaty-country resident whose dividends were withheld at 30% may be entitled to a 15% rate, but the only way to recover that 15% difference is to file Form 1040-NR and claim it.

The deadline is 15 April after the tax year, with an automatic extension to 15 June for non-residents who have no US wages. An extension of time to file is not an extension of time to pay, interest runs from the original due date.

Tax treaties: reducing the 30% rate

The United States has income tax treaties with more than 60 countries, and they can cut the withholding rate on many income types, sometimes to zero.

The United States has income tax treaties with more than 60 countries, and they can cut the withholding rate on many income types, sometimes to zero. The mechanism is simple: you certify your treaty eligibility on Form W-8BEN (for individuals) and give it to your withholding agent before or at the time of payment, so the agent withholds at the treaty rate instead of 30%.

If the W-8BEN did not reach the agent in time and too much was withheld, you recover the excess by filing Form 1040-NR and attaching the treaty-based position. The refund is processed against the withholding already remitted for you.

Treaty claims are never automatic, you have to cite the correct article, satisfy any limitation on benefits (LOB) provision, and prove your residency in the treaty country. A vague claim without that supporting detail tends to be delayed or refused.

ITIN: the number everything else depends on

An ITIN is the nine-digit IRS number that non-residents who cannot get a Social Security Number need in order to file at all.

An ITIN is the nine-digit IRS number that non-residents who cannot get a Social Security Number need in order to file at all. Without one, you cannot file a US return, claim a treaty benefit on a return, or be identified as a foreign owner on certain entity filings, it is the key that unlocks everything else.

You apply on Form W-7, usually attached to the return that requires it. Processing normally takes six to eight weeks, longer in peak season. And an ITIN that has gone unused on a federal return for three consecutive years expires, and must be renewed before you can use it again.

State filing obligations

A federal return is only half the story, most income-tax states also require a non-resident return where income is sourced to that state.

A federal return is only half the story, most income-tax states also require a non-resident return where income is sourced to that state. Rental property in New York, consulting fees earned in California, or a partnership interest in Texas (no income tax, but a franchise tax) each carry their own separate obligation.

State rules differ widely on rates, deductions, and filing thresholds. A non-resident who files federally but overlooks the state return risks penalties and interest from both sides, since states and the IRS share taxpayer information.

What happens if you do not file

The most common outcome is simply overpaying, the 30% stays with the IRS, treaty benefits go unclaimed, and deductions are lost.

The most common outcome is simply overpaying, the 30% stays with the IRS, treaty benefits go unclaimed, and deductions against effectively connected income are lost. For non-residents with ECI, the failure-to-file penalty under IRC § 6651(a)(1) is 5% of the unpaid tax per month, up to 25%. There is no statute of limitations on an unfiled return, so the IRS can assess tax at any point in the future.

For anyone who has missed prior years, the IRS Streamlined Filing Compliance Procedures or a reasonable-cause statement may bring things current without the full penalty weight, but only where the non-compliance was non-willful.

Taxule US Tax & Accounting Partner | General information, not personal tax advice. Confirm your position with a qualified adviser before filing.