UK citizens generally do not have to file a US tax return if they live and work in the United Kingdom and have no US-source income. A filing obligation kicks in only when you earn money from US sources that wasn’t fully taxed at source, run a trade or business in the country, spend enough days on US soil to be classed as a resident, or want to claim a refund or treaty benefit. Whether you owe anything, and whether you need to file to prove it, comes down to the type of income and how much time you spent in the country.
Are You a Nonresident for US Tax Purposes?
Everything else follows from this question. If you’re not a US citizen or green card holder, the IRS treats you as a nonresident alien unless you meet the Substantial Presence Test.1Internal Revenue Service. Determining an Individual’s Tax Residency Status
You meet that test if you were physically present in the US for at least 31 days during the current year and at least 183 days across the current year and the two prior years, using a weighted count: every day in the current year counts fully, each day in the prior year counts as one-third, and each day in the year before that counts as one-sixth.2Internal Revenue Service. Substantial Presence Test
Even if the count trips, a closer connection exception can preserve nonresident status. You must have been in the US fewer than 183 days during the current year, kept a tax home in the UK all year, had a closer connection to the UK than to the US, and taken no steps toward a green card.3Internal Revenue Service. Closer Connection Exception to the Substantial Presence Test
Most UK citizens living in the UK are well clear of these day counts. The rest of this article assumes that.
When Filing Is Actually Required
A nonresident alien files Form 1040-NR when any of the following applies:4Internal Revenue Service. Taxation of Nonresident Aliens
- You were engaged in a US trade or business during the year. That covers performing personal services while physically in the country, running a US sole proprietorship, or earning income through a US partnership. The filing duty stands even if the business ran at a loss.
- You had US-source income where tax wasn’t fully withheld at the correct rate. If a US payer should have withheld and didn’t, or didn’t withhold enough, you need to file and settle the balance.
- You want a refund of over-withheld tax, or you want to claim a treaty benefit, a deduction, or a special election (such as the Section 871(d) election that lets US rental income be taxed on a net basis).
The first bucket, income earned through active work or business in the US, is called effectively connected income. It’s taxed at the same graduated rates that apply to US citizens, and you can claim deductions against it, but only itemized ones tied to that income; the standard deduction isn’t available to nonresident aliens.5Internal Revenue Service. Instructions for Form 1040-NR – U.S. Nonresident Alien Income Tax Return
When You Don’t Have to File
If your only US income is passive (dividends, interest, royalties) and the US payer already withheld the correct amount of tax at source, you generally have no filing requirement. The withholding is the final tax.
Capital gains from selling US stocks and other securities are a related surprise: for a nonresident alien present in the US fewer than 183 days during the tax year, portfolio gains are generally not subject to US tax at all. That exemption does not extend to gains from US real property, which are handled under the FIRPTA rules below.
Rental income from US property is the trickier case. By default, gross rent is taxed at a flat 30% with no deduction for mortgage interest, property taxes, or repairs. Section 871(d) lets you elect to have that income treated as effectively connected instead, so you pay graduated rates on net profit rather than 30% of the gross.6Office of the Law Revision Counsel. 26 U.S. Code 871 – Tax on Nonresident Alien Individuals Making the election requires filing a US return, and once revoked, you can’t re-elect for five years.7Internal Revenue Service. Nonresident Aliens – Real Property Located in the U.S.
How the US-UK Tax Treaty Changes the Picture
The default US tax on FDAP income (fixed, determinable, annual, or periodical payments such as dividends and interest) is 30% of the gross amount, withheld at source.8Internal Revenue Service. Fixed, Determinable, Annual, or Periodical (FDAP) Income The US-UK Income Tax Treaty cuts that sharply for UK residents who are the beneficial owners of the income:9Internal Revenue Service. Tax Treaty Tables
- Dividends drop to 15% for most individual investors, or 5% if you own at least 10% of the voting power in the paying company.
- Interest is generally reduced to 0%.
- Royalties are generally reduced to 0%.
These lower rates aren’t automatic. You either give the US payer a Form W-8BEN before payment, so they withhold at the treaty rate, or you file a US return afterward to reclaim the excess. The W-8BEN route avoids a filing obligation; the refund route creates one.
If you take a treaty position on a return (say, to reduce a withholding tax that would otherwise apply), you must attach Form 8833 identifying the article you’re relying on.10Internal Revenue Service. Form 8833 – Treaty-Based Return Position Disclosure Under Section 6114 or 7701(b) Skipping it when required carries a $1,000 penalty per failure.11Office of the Law Revision Counsel. 26 U.S. Code 6712
Pension income has its own treaty treatment. Regular distributions from a US pension to a UK resident are taxable only in the UK, and US Social Security paid to a UK resident is likewise taxable only in the UK. Lump-sum payments from a US pension scheme go the other way: they are taxable only in the US.12Legislation.gov.uk. The Double Taxation Relief (Taxes on Income) (The United States of America) Order 2002
Selling US Property: FIRPTA Almost Always Means Filing
If you sell US real estate as a nonresident, the buyer must withhold 15% of the gross sale price under the Foreign Investment in Real Property Tax Act and send it to the IRS. Withholding applies whether or not you made a profit.13Internal Revenue Service. FIRPTA Withholding
Two exceptions cover smaller personal residences. No withholding applies if the buyer acquires the property to use as a personal residence and pays no more than $300,000.14Internal Revenue Service. Exceptions From FIRPTA Withholding Between $300,001 and $1,000,000, withholding drops to 10% if the buyer will use the property as a residence.15Office of the Law Revision Counsel. 26 U.S. Code 1445 – Withholding of Tax on Dispositions of United States Real Property Interests
The withheld amount is an advance payment, not the final tax. You file Form 1040-NR after the sale to report the actual gain, calculate the real liability, and claim any refund. If you know in advance that your tax will be lower than 15% of the sale price, you can apply for a withholding certificate using Form 8288-B before closing; the IRS allows up to 90 days to process these, so start early.
Forms, ITIN, and Deadlines
The return itself is Form 1040-NR.16Internal Revenue Service. About Form 1040-NR, U.S. Nonresident Alien Income Tax Return It separates effectively connected income, taxed at graduated rates with deductions, from FDAP income, taxed at 30% or the lower treaty rate.
To file, you need either a Social Security Number or an Individual Taxpayer Identification Number. Most UK citizens without US work authorization need an ITIN, which you apply for on Form W-7, usually submitted with the return itself.17Internal Revenue Service. Instructions for Form W-7 – Application for IRS Individual Taxpayer Identification Number Processing runs about seven weeks, longer during tax season or from abroad. A Certifying Acceptance Agent can authenticate your passport in person, so you don’t have to mail the original to the IRS.18Internal Revenue Service. How to Apply for an ITIN
The filing deadline depends on the income. If you received US wages subject to income tax withholding, the return is due April 15. If you didn’t (for example, your only US income was investment income), the deadline is automatically June 15. Tax owed is still due by April 15 to avoid interest.19Internal Revenue Service. Instructions for Form 1040-NR (2025)
Form 1040-NR can be e-filed, and paid preparers are generally required to file it that way. E-filing gives you immediate acknowledgment of receipt, which is useful when you’re tracking the return from overseas.
Penalties and Catching Up
Miss a deadline with tax owed and two penalties run in parallel. Failure to file is 5% of the unpaid tax per month, capped at 25%. Failure to pay adds 0.5% per month, also capped at 25%. Interest sits on top of both.20Office of the Law Revision Counsel. 26 U.S. Code 6651 If you owed nothing, there’s no monetary penalty, but you lose the ability to claim refunds or elections that require a filed return.
If you should have been filing and weren’t, the Streamlined Foreign Offshore Procedures are the usual way back in. You need to show the failure was non-willful, meaning negligence, an honest mistake, or a good-faith misunderstanding rather than deliberate evasion, and the IRS must not already have opened an examination or criminal investigation.21Internal Revenue Service. Streamlined Filing Compliance Procedures For nonresidents, the program adds no penalty beyond taxes and interest owed.
State Tax Is a Separate Question
A federal filing obligation, or the lack of one, tells you nothing about state tax. If you earned wages or business income while working in a particular state, or own rental property there, that state may want its own return. Some states have no income tax; others expect nonresidents to file with modest amounts of in-state income. Check the rules for the specific state your US income touched.