US expat taxes in the UK (2026): Filing, deadlines, and double-tax relief

Written by  Mel Whitney, EA

Last updated Jun 30, 2026

If you are a US citizen or Green Card holder living in the UK, you still file a US federal return on worldwide income, even if all your UK income was taxed through PAYE.

Most US expats in the UK owe little or no additional US income tax after claiming the Foreign Tax Credit (FTC) or the Foreign Earned Income Exclusion (FEIE, $130,000 for the 2025 tax year filed in 2026).

This guide covers the 2025 tax year filed in 2026, including UK filing obligations, FIG regime rules, and double-tax relief methods.

Key facts (2025 tax year, filed in 2026)

• US filing requirement: US citizens and Green Card holders abroad generally follow the same filing rules as taxpayers in the US. For 2025, the standard deduction is $15,750 for single filers and married filing separately, $31,500 for married filing jointly, and $23,625 for head of household, but the actual filing requirement depends on filing status, age, dependency status, self-employment income, and other facts.
• Primary double-tax relief: the Foreign Tax Credit (Form 1116) is the most effective method for UK-employed expats, because UK rates (up to 45%) often exceed US rates (up to 37%).
• FEIE limit: $130,000 per qualifying person for the 2025 tax year filed in 2026. The figure rises to $132,900 for the 2026 tax year filed in 2027.
• Automatic filing extension: June 15, 2026, for taxpayers living abroad on the regular due date. No Form 4868 is needed, but the return should include a statement showing the taxpayer qualifies.
• Extended deadline: October 15, 2026, via Form 4868.
• FBAR threshold: aggregate foreign accounts exceeding $10,000 at any point during the 2025 calendar year.
• Form 8938 threshold (abroad, single filer): more than $200,000 on the last day of the 2025 tax year, or more than $300,000 at any time during the year.
• FIG regime: eligible new UK residents can claim relief on qualifying foreign income and gains for up to four tax years from 6 April 2025. Foreign employment income is handled separately: qualifying foreign workdays may be eligible for Overseas Workday Relief rather than the main FIG income-and-gains claim.
• Scotland note: the Scottish income tax top rate is 48% on income over £125,140 in 2025/26.

What taxes do I file in the UK?

UK income tax rates for 2025/26 range from 20% (basic rate on income £12,571–£50,270) to 45% (additional rate on income over £125,140) for taxpayers in England, Wales, and Northern Ireland.

Most US expats in the UK pay UK tax via PAYE and do not file Self Assessment unless they have self-employment income, rental income, or untaxed investment income.

You may still file a US return on worldwide income, but double taxation is usually reduced through FTC, FEIE, and (when needed) the US–UK tax treaty.

Key facts (UK filing reality)

• The UK tax year runs from 6 April to 5 April (not the US calendar year).
• Many employees pay UK tax via PAYE and don't file a Self Assessment every year.
• Self assessment is common if you're self-employed, a landlord, or have untaxed income.
• UK and US filing deadlines do not line up; plan for two calendars.
• UK income tax is often high enough that the FTC can offset most US income tax.
• You may still owe US tax on certain categories (for example, US-source income or timing differences).
• FBAR and Form 8938 reporting are separate from your UK filing.
• UK tax residency affects what the UK taxes, not whether you must file US taxes.
• Newer arrivals should pay attention to the four-year foreign income and gains (FIG) regime starting 6 April 2025.

Practical visa and relocation steps for Americans moving to Britain are covered in our guide to moving to the UK.

UK vs US: fast comparison

A US expat in the UK may have to manage two tax systems with different year-end dates: the US tax year runs January 1–December 31, while the UK tax year runs April 6–April 5. Many PAYE-only UK employees do not file Self Assessment every year, but US filing may still be required.

US expat taxes in the UK can stack up fast – here's what to do next.

Learn more

What are the 2026 US deadlines?

The 2026 US filing deadline for the 2025 tax year is April 15, 2026. The deadlines below apply to US citizens and Green Card holders filing the 2025 tax return in 2026.

If you're living outside the US on April 15, you generally get an automatic extension to June 15, 2026 to file. No Form 4868 is needed for this extension, but your return should include a statement showing you qualify. You can extend further to October 15, 2026 by filing Form 4868.

These dates are the anchor points for US taxes for expats in UK filing the 2025 tax year in 2026.

Three filing windows shape US tax planning for expats in the UK: the standard April deadline, the automatic two-month extension for taxpayers abroad, and the October extension via Form 4868.

Payments and extensions follow three quick rules:

• An extension gives you more time to file, not more time to pay.
• Interest generally starts if tax isn't paid by the regular due date.
• If you need extra time specifically to qualify for FEIE (bona fide residence or physical presence), Form 2350 may apply.

The mechanics of choosing between Form 4868 and Form 2350 depend on whether you need time to file or time to qualify for FEIE.

Do I still need to file US taxes?

US citizens and Green Card holders living in the UK must file a US federal tax return if gross income meets the IRS filing threshold for their filing status, regardless of whether UK tax was withheld via PAYE. The US generally taxes citizens and Green Card holders on worldwide income, even if you live in the UK.

In many cases, you'll owe little or no US income tax after credits or exclusions, but the filing and reporting rules still apply.

The following factors commonly make filing necessary or advisable:

• Your income exceeds the IRS filing threshold for your filing status.
• To claim FTC or FEIE, you must file a US return.
• Many expats have extra reporting: FBAR, Form 8938, and sometimes other international forms.
• You may have US-source income (US dividends, rental income, capital gains, retirement distributions).
• You may want to preserve benefits like foreign tax credit carryovers.
• If you're behind, the cost of catching up can grow, and certain IRS relief programs require specific filing patterns.

The worldwide income rule for Americans abroad is set out in IRS Publication 54, which explains how citizenship-based taxation, FEIE, and FTC interact for US citizens overseas.

The filing picture changes slightly when both passports are involved; we cover this in our guide to US–UK dual citizenship taxes.

Living in the UK still means US expat taxes in the UK – filing is usually required.

Learn more

What forms do I need to file?

Most US expats start with Form 1040, then add expat-specific forms based on income type, accounts, and assets. On the UK side, many people mainly need documents like a P60 or P45, and only file Self Assessment forms when HMRC requires it.

A forms-first approach works best for US taxes for expats in UK, because the reporting is often where complexity shows up.

Common US forms for expats in the UK

For US expats in the UK, Form 1040 is universal; FTC (Form 1116) and FEIE (Form 2555) handle double-tax relief; FBAR and Form 8938 catch foreign account and asset reporting; and Forms 8621 and 8833 cover ISA/PFIC and treaty positions.

Common UK documents and forms you may run into

For most US expats in the UK, the UK paperwork comes down to one of two situations: PAYE employees rely on P60 and P45 summaries, and Self Assessment filers add SA100 (with SA105 or SA109 supplementary pages where relevant).

Because the UK and US tax years do not match, a UK P60 for 2025/26 may include pay and tax from both the 2025 and 2026 US calendar years. When preparing the 2025 US return, allocate UK income and UK tax carefully so Form 1116 reflects only the relevant 2025 US tax-year amounts.

Will I need to pay tax twice?

Usually not on the same income. For most US expats in the UK, double taxation is reduced using the Foreign Tax Credit (most common in the UK), the Foreign Earned Income Exclusion (for earned income), and sometimes treaty positions for specific categories like pensions. The right approach depends on your income mix and timing.

FTC vs FEIE (UK-focused comparison)

For many UK-taxed salaries, the FTC often eliminates most or all US income tax, but the result depends on source rules, timing, income category, and Form 1116 limitations; FEIE is mainly useful for earned income in lower-tax situations or where excluding income improves cash flow.

Step-by-step filing decision process

The following five-step process applies to most US expats in the UK choosing between FTC and FEIE:

1. List your income types: salary, bonus, self-employment, rental, dividends and interest, capital gains, pensions.
2. Confirm where it's taxed first (UK vs US source rules) and whether UK tax was actually paid.
3. Run FTC first if most of your income is UK-taxed salary and you have passive income; this is often the cleanest UK outcome.
4. Test FEIE if you have earned income and lower UK tax on that income, or if you want the exclusion for cash-flow reasons.
5. Check interactions: self-employment tax (separate from income tax), pension or ISA reporting, and whether you're mixing FTC and FEIE (allowed, but not on the same income).

Two UK-specific trade-offs are worth flagging:

• ISAs: tax-free in the UK does not automatically mean tax-free to the IRS; reporting can also get complicated if the ISA holds non-US funds.
• UK pensions: treaty language can help, but reporting positions vary and may trigger additional IRS forms.

Do I need the US–UK tax treaty?

Most expats never invoke the US–UK tax treaty directly because FTC and FEIE already eliminate most double taxation. The treaty matters when you need residency tie-break rules, specific rules for pensions, lump sums, or social security, or reduced withholding on certain passive income.

Treaty positions matter most in three scenarios:

• You're a dual resident under local rules and need tie-break clarity.
• You have UK pension distributions, including potential lump sums.
• You're relying on treaty language for a specific income category or disclosure position.

What the treaty does NOT do: it does not remove the general US rule that US citizens file US returns on worldwide income. The US–UK tax treaty does not exempt US citizens from filing a US return; US citizens file based on citizenship, not treaty residence status.

A full article-by-article walkthrough is in our US–UK tax treaty guide.

Am I a UK tax resident?

UK tax residence affects what the UK taxes (worldwide vs UK-source) and whether Self Assessment is likely. It does not change the US rule that US citizens and Green Card holders generally report worldwide income.

UK tax residency is determined mainly by the Statutory Residence Test (SRT), based on days in the UK and ties. Day-counting rules and the full tie-breaker logic are set out in HMRC's Statutory Residence Test guidance.

For US citizens in the UK, UK residency does not change US filing duties, but it does change which UK return applies: UK residents are generally taxed on worldwide income and more likely to need Self Assessment, while non-residents are taxed mainly on UK-source income.

Who is considered a resident of the UK?

Three common triggers establish UK tax residency under the SRT:

• 183 or more days in the UK in a tax year.
• A UK home test that's met (facts matter).
• Enough UK ties combined with enough UK days (family, accommodation, work, 90-day ties, plus a "country tie" in some cases).

Split-year rules and exceptional-circumstances day counting can change outcomes, so if your move dates matter, it's worth checking.

The 4-year FIG regime: rules for new UK arrivals from 6 April 2025

The foreign income and gains (FIG) regime replaced the remittance basis on 6 April 2025.

Eligible new UK residents pay no UK tax on qualifying foreign income and gains for up to four tax years, provided they have been non-UK resident for at least 10 consecutive prior tax years.

HMRC publishes an eligibility tool, check if you can claim the FIG regime, that walks through the qualifying conditions step by step.

Six points cover how the FIG regime works in practice:

• Eligibility trigger: first year of UK tax residency under the Statutory Residence Test after a 10-year absence from UK residence.
• Duration: maximum four tax years; years cannot be rolled over or deferred.
• What qualifies for FIG relief: dividends from non-UK companies, interest on foreign bank accounts, overseas property profits, and foreign capital gains.
• What does NOT qualify: foreign employment income is not covered by the main FIG income-and-gains relief. Qualifying foreign workdays may be eligible for Overseas Workday Relief instead.
• Trade-off: claiming FIG relief means losing the Personal Allowance (£12,570) and the CGT annual exempt amount (£3,000).
• US expat note: FIG reduces UK tax on eligible foreign income only. US filing obligations (Form 1040, FBAR, Form 8938) are entirely unaffected by FIG eligibility.

Pre-move planning steps for Americans relocating to Britain are in our UK relocation tax checklist.

Which UK taxes matter most?

UK income tax, National Insurance (NI), capital gains tax (CGT), and inheritance tax (IHT) are the four taxes most relevant to US expats in the UK. The UK income tax additional rate is 45% on income over £125,140; the UK IHT rate is 40% on taxable estates above the £325,000 nil-rate band.

For US expats in the UK, income tax is the main driver of FTC planning, National Insurance is handled separately through the totalization agreement, capital gains tax often catches UK property sellers off guard, and inheritance tax matters whenever UK-situs assets are involved.

Personal income tax rates

The UK tax bands depend on where you live in the UK. For England, Wales, and Northern Ireland, the standard 2025/26 bands are as follows:

Income tax rates in Scotland

What is National Insurance?

National Insurance (NI) is the UK's social contribution system and is separate from income tax.

Employees typically pay Class 1 through payroll at 8% on earnings between £12,570 and £50,270 and 2% above £50,270 (2025/26 rates). Self-employed people may pay Class 4 at 6% on profits between £12,570 and £50,270 and 2% above, through Self Assessment.

Four NI points matter most for National Insurance UK expats planning:

• Employee vs self-employed NI rules differ (Class 1 vs Class 4).
• NI is not the same as income tax, and FTC treatment is not automatic.
• Self-employed NI is paid through Self Assessment.
• Totalization: under the US–UK totalization agreement you may be able to contribute to only one system (US Social Security or UK NI) and use a certificate of coverage.

How is the UK capital gains tax taxed?

For the UK tax year 2025/26, most individual capital gains are taxed at 18% or 24%, depending on the taxpayer's income position, excluding special categories such as carried interest. The annual exempt amount is £3,000. UK CGT most often shows up for US expats when they sell investments or UK property.

Three points matter most for US expats holding UK property:

• Property sales are a common trigger for expats.
• The US also taxes worldwide gains; FTC may apply, but timing can differ.
• FX and cost-basis differences can create a gain in one country but not the other.

Cost-basis adjustments, FX translation, and Form 1116 mechanics for UK property sales are covered in our UK property CGT guide.

Sold UK property? Don't assume it nets out – US expat taxes in the UK can differ.

Learn more

Does UK inheritance tax affect me?

UK inheritance tax can matter if you hold UK-situs assets or, from 6 April 2025, if you are a long-term UK resident. Long-term UK residence generally means being UK resident for at least 10 of the previous 20 tax years, with tail rules after leaving the UK.

The rules are separate from the US estate tax, and cross-border families sometimes need the US–UK estate tax treaty layer (if applicable) to prevent double taxation in estate scenarios.

• The UK has nil-rate band rules that can shelter part of an estate.
• Residency and asset location can change what's in scope.
• Estate issues are high-stakes; get tailored help early.

What income is taxed in the UK?

UK-resident individuals pay UK income tax on worldwide income and gains under the arising basis.

New arrivals who qualify for the FIG regime may claim relief on eligible foreign income and gains for up to four years. Foreign employment income is not covered by the main FIG relief but may qualify under the separate Overseas Workday Relief regime.

Seven expat-relevant categories are worth keeping on your radar:

• Salary, bonuses, and benefits.
• Self-employment and contracting income.
• UK rental income (and sometimes overseas rentals).
• Interest, dividends, and investment income.
• Capital gains (especially UK property).
• Pensions and pension lump sums.
• ISAs: tax-free in the UK, but not automatically tax-free to the IRS.

Filing income tax returns in the UK

If you're on PAYE only, you may not file Self Assessment UK. If you do need to file, the process is mostly a checklist: register, collect documents, file, and pay on time. The key is matching the UK tax year and deadlines to what you're doing for your US return.

The following six-step checklist covers the typical Self Assessment cycle:

1. Confirm if you must file a Self Assessment (self-employed, landlord, untaxed income, HMRC notice).
2. Register if needed (often due by 5 October following the end of the tax year).
3. Collect UK tax documents: P60 or P45, dividend and interest statements, rental summaries, pension statements.
4. File your return: paper is due earlier than online.
5. Pay what you owe by the payment deadline.
6. Plan for payments on account if they apply (typically Jan 31 and Jul 31).

The typical micro timeline follows a fixed pattern:

• Tax year ends 5 April.
• Registration for first-time Self Assessment is often due 5 October.
• Online filing and balancing payment are usually due on 31 January.
• Second payment on account (if applicable) due 31 July.

Making Tax Digital for income tax: what changes from 6 April 2026

Making Tax Digital for Income Tax (MTD for IT) becomes mandatory from 6 April 2026 for self-employed individuals and landlords whose qualifying income exceeded £50,000 in the 2024/25 tax year.

MTD for Income Tax requires affected sole traders and landlords to keep digital records, send quarterly income-and-expense summaries using compatible software, and submit their Self Assessment tax return through that software. The quarterly updates are summaries, not tax returns.

Registration runs through HMRC's Making Tax Digital sign-up service, which also lists the approved software providers.

The MTD for IT rollout follows a three-phase threshold schedule:

• From 6 April 2026: qualifying income (self-employment plus UK property) over £50,000 in the 2024/25 tax year.
• From 6 April 2027: qualifying income over £30,000.
• From 6 April 2028: qualifying income over £20,000.
• First quarterly submission deadline: 7 August 2026 (covering 6 April–5 July 2026).
• Not affected: employees on PAYE only, with no qualifying self-employment or rental income.

The full year-end mechanics of preparing Form 1040 from UK records are in our step-by-step US filing guide for the UK.

How do UK pensions affect US taxes?

UK pension income paid to a US citizen is generally reportable on the US federal return. The US–UK treaty may affect some pension positions, but US citizens must account for the treaty's saving clause, which often preserves US taxing rights. Pension distributions and lump sums should be reviewed before relying on Article 17.

If you take a treaty-based return position that reduces US tax, you generally disclose it on Form 8833 (Treaty-Based Return Position Disclosure) unless an exception applies. Do not assume every UK pension item is "UK-only" for a US citizen.

Article 17 mechanics, including the saving clause and the 25% lump sum question, are explained in our Article 17 pension treaty guide.

The following five UK pension scenarios create the most common US reporting issues for expats:

• Pension reporting positions can vary depending on plan type.
• Lump sums may have different treatment under treaty language than regular pension income.
• Investments inside pensions (or alongside pensions) can trigger PFIC reporting.
• Employer contributions and growth may have different US timing concepts.
• Retirement and estate consequences can differ between systems.

If you're drawing a pension soon, verify the US treatment today.

Learn more

Real-life scenarios

Tax rules are easier to follow once you see how they combine on an actual return. The scenarios below are based on common TFX client situations – names and details changed – showing how UK and US obligations overlap and where the real compliance pressure points tend to land.

Scenario 1: London employee choosing FTC vs FEIE

A US citizen on a UK employment contract in London had PAYE withhold UK income tax all year in 2025 and held a UK savings account alongside her salary.

• On the UK side, her UK tax was paid through PAYE, and no Self Assessment was required because she had no untaxed income.
• On the US side, she filed Form 1040. Because her UK taxes were substantial, the Foreign Tax Credit wiped out most US income tax on her salary. She still filed FBAR and checked whether Form 8938 applied.
• Outcome: low or no US income tax, but extra reporting.

Scenario 2: Side hustle triggers UK Self Assessment

A US citizen worked a UK PAYE job and also had freelance design income plus a small UK rental property in 2025.

• On the UK side, HMRC required Self Assessment, so the client filed SA100 plus supplementary pages and paid any balancing amount by the UK deadline.
• On the US side, the client reported worldwide income; the FTC helped, but the client also checked whether self-employment tax applied and whether totalization rules affected social contributions.
• Outcome: more forms, but manageable with good records.

Scenario 3: ISA and pension reporting trap

A US citizen held a Stocks & Shares ISA and contributed to a UK workplace pension in 2025.

• On the UK side, the ISA was tax-free, and the workplace pension contributions reduced UK taxable income.
• On the US side, the ISA was not automatically tax-free. If the ISA held non-US funds treated as PFICs, extra US reporting, such as Form 8621, could apply. Pension distributions later would be affected by treaty language, and some reporting positions were nuanced.
• Outcome: no immediate UK issue, but US compliance risk if the client had assumed "tax-free in the UK = tax-free in the US."

Scenario 4: Self-employed and years behind on US filing

A dual US-Australian citizen ran a private therapy practice in York. She left the US years earlier and paid her UK taxes through HMRC, but she was still required to catch up on US filing because she remained a US citizen.

• On the UK side, her income tax and Class 4 NI were paid correctly through Self Assessment each year.
• On the US side, she was several years behind on Form 1040 and FBAR filings. Under the Streamlined Foreign Offshore Procedures, she filed the most recent three years of delinquent returns, six years of FBARs, certified non-willful conduct, and paid any tax and interest due. Because she qualified and followed the procedures, specified IRS and FBAR penalties generally did not apply.
• Outcome: fully compliant, with penalties generally avoided, and proof that paying UK tax doesn't cancel the US filing requirement.

Scenario 4: FIG regime claimant with US brokerage income

A US software engineer relocated to London in October 2025 after 12 years of US-only tax residency. The client qualified for the FIG regime from 2025/26.

• On the UK side, the client claimed FIG relief on $52,000 of qualifying US brokerage dividends and foreign gains for 2025/26, so the remittance to a UK bank account did not itself create UK tax under the new FIG regime. The claim would be made through Self Assessment, and claiming FIG can affect UK allowances. UK employment income from a London employer was taxed normally via PAYE.
• On the US side, all $52,000 remained reportable on Form 1040 Schedule B and Schedule D. FBAR filing was required because the UK current account balance exceeded $10,000. FIG status changed the client's UK tax bill only; the US filing position was unchanged.
• Outcome: UK tax saving, but no change to US filing duties.

What are common expat mistakes?

Most problems with US expat taxes in the UK aren't about paying extra tax; they're about missing forms.

• Skipping US filing because PAYE already withheld UK tax.
• Missing the FBAR filing deadline: non-willful violations can carry an inflation-adjusted civil penalty up to $16,536 per FBAR report, while willful violations can be much higher – up to the greater of the inflation-adjusted statutory amount or 50% of the account balance, depending on the facts.
• Skipping Form 8938: the failure-to-file penalty is $10,000, rising to $50,000 if not filed after IRS notice. US citizens living abroad may need Form 8938 if specified foreign financial assets exceed the applicable threshold – for an unmarried taxpayer abroad, more than $200,000 on the last day of the year or more than $300,000 at any time during the year.
• Treating ISAs as US tax-free or ignoring PFIC exposure.
• Assuming FEIE eliminates all US obligations (it doesn't, and it doesn't remove self-employment tax).
• Misunderstanding UK split-year timing when you move mid-year.
• Mixing FTC and FEIE incorrectly (claiming credits on excluded income).
• Forgetting UK Self Assessment triggers (rental income, self-employment, untaxed income).
• Assuming the FIG regime removes the US filing requirement: FIG reduces UK tax on qualifying foreign income and gains for up to four years; US citizens still file Form 1040 and report all worldwide income regardless of FIG status.

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Mel Whitney

EA

Mel Whitney, an EA with TFX, has 15 years of tax experience and a BS in Accounting from Humboldt State University. He excels in expatriate services, providing client-focused solutions.

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