US expat taxes in the UK (2026): Filing, deadlines, and double-tax relief
If you’re a US citizen living in the UK, you usually file a US federal return and may also file a UK return. Double tax is typically avoided using the Foreign Tax Credit (FTC), the Foreign Earned Income Exclusion (FEIE), and sometimes the US–UK tax treaty. This guide covers the 2025 tax year filed in 2026.
Most Americans in the UK must file a US Form 1040 even if they owe $0. UK tax paid often reduces US tax through the Foreign Tax Credit, while the FEIE can exclude some earned income. Extra reporting (FBAR/8938) is common and is where many mistakes happen.
What taxes do I file in the UK?
Most US expats deal with UK income tax and National Insurance through PAYE, and file Self Assessment only when HMRC requires it (for example, selfemployment, rental income, or significant untaxed income). You may still file a US return on worldwide income, but double taxation is usually reduced through FTC/FEIE and (when needed) the 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 Self Assessment every year.
- Self Assessment is common if you’re selfemployed, 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, USsource 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 4year foreign income and gains (FIG) regime starting 6 April 2025.
UK vs US: fast comparison
| Topic | United States | United Kingdom |
|---|---|---|
| Tax year | Calendar year (Jan 1 – Dec 31) | Apr 6 – Apr 5 |
| Basis of taxation | Citizenship-based (worldwide income for US citizens/Green Card holders) | Residence-based (worldwide income for residents; limited for nonresidents) |
| Headline filing deadline | 2025 return due Apr 15, 2026 (most taxpayers) | Self Assessment online is usually due Jan 31, after the tax year ends |
What are the 2026 US deadlines?
The 2026 US deadline for the 2025 tax year is April 15, 2026 – a key date for anyone navigating US expat taxes UK. If you’re living outside the US on April 15, you generally get an automatic extension to June 15, 2026, to file (no form required), and you can extend further to October 15, 2026, by filing an extension.
These dates are the anchor points for US taxes for expats in UK filing for the 2025 tax year.
| Deadline (2026) | Who it applies to | What it is |
|---|---|---|
| Apr 15, 2026 | Most filers | File and pay deadline for the 2025 return |
| Jun 15, 2026 | Taxpayers living abroad on Apr 15 | Automatic 2month filing extension (statement required with return) |
| Oct 15, 2026 | Filers who request an extension | File deadline after Form 4868 extension |
Payments and extensions (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.
Do I still need to file US taxes?
Usually, yes. The US generally taxes citizens and Green Card holders on worldwide income, even if you live in the UK and even if UK tax was withheld. In many cases, you’ll owe little or no US income tax after credits or exclusions – but the filing and reporting rules still apply.
Here are common reasons US expats in the UK still file (even when they owe $0):
- It’s a filing requirement based on income and status (and it keeps you compliant).
- 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 USsource 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.
What forms do I need 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/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.
| Form | When it’s common | Why it matters |
|---|---|---|
| Form 1040 | Almost always | Your main US return |
| Form 1116 (FTC) | UK taxes paid on income | Credits can reduce US tax dollar-for-dollar |
| Form 2555 (FEIE) | Foreign earned income + qualifying tests | Excludes up to the annual limit of earned income |
| FBAR (FinCEN 114) | Foreign accounts over $10k aggregate | Separate annual reporting – filed online |
| Form 8938 | Higher foreign asset totals | FATCA asset reporting (different thresholds than FBAR) |
| Form 8621 | UK funds/ETFs treated as PFICs | Common ISA/pension investment pitfall |
| Form 8833 | Taking a treaty-based position | Required for certain treaty disclosures |
Common UK documents/forms you may run into
| Document/form | When it’s common | What it’s for |
|---|---|---|
| P60 | If employed on 5 April | Summary of pay and tax withheld via PAYE |
| P45 | If you leave a job | Pay and tax to date in the UK tax year |
| SA100 | If you file a Self Assessment | Main UK tax return |
| SA105 | If you have UK rental income | UK property supplementary pages |
| SA109 | Residence status, split year, non-resident issues | Residence-related supplementary pages |
Practical note: US and UK forms often don’t “map” cleanly because the tax years differ. Good record-keeping (dates, pay periods, statements) prevents rework.
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)
| Feature | Foreign tax credit (FTC) | Foreign earned income exclusion (FEIE) |
|---|---|---|
| Best for | UK-taxed earned income and many passive categories | Earned income where exclusion gives a better result |
| Income covered | Earned and some passive income (by category) | Earned income only |
| How it works | Keeps income on return; offsets US tax with credits | Excludes earned income up to the annual limit |
| Carryover | Unused credits may carry to other years (rules apply) | No carryover – it’s an exclusion |
| Common UK trade-offs | Often strong because UK tax rates can exceed US rates | Can reduce the ability to use certain US benefits tied to taxable compensation; doesn’t help most passive income |
Step-by-step filing decision process
- List your income types: salary, bonus, self-employment, rental, dividends/interest, capital gains, pensions.
- Confirm where it’s taxed first (UK vs US source rules) and whether UK tax was actually paid.
- Run FTC first if most of your income is UK-taxed salary and you have passive income – this is often the cleanest UK outcome.
- Test FEIE if you have earned income and lower UK tax on that income, or if you want the exclusion for cash-flow reasons.
- Check interactions: self-employment tax (separate from income tax), pension/ISA reporting, and whether you’re mixing FTC and FEIE (allowed, but not on the same income).
UK-specific trade-offs:
- 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 “use the US-UK tax treaty” directly because FTC/FEIE already eliminates most double taxation. The treaty matters when you need
(1) residency tie-break rules,
(2) specific rules for pensions/lump sums/social security, or
(3) reduced withholding on certain passive income.
When treaty positions matter most:
- 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.
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 residence is determined mainly by the Statutory Residence Test (SRT), based on days in the UK and ties.
| Status | What the UK generally taxes | What changes for filing |
|---|---|---|
| UK resident | Worldwide income and gains (with exceptions and special regimes) | More likely to need Self Assessment depending on income types |
| Non-resident | Generally, UK-source income (and certain UK gains) | You may still have UK filing duties for UK-source items |
Who is considered a resident of the UK?
Three common triggers are:
- 183+ 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 – if your move dates matter, it’s worth checking.
Non-dom rules: what changed?
From 6 April 2025, the UK introduced a 4-year foreign income and gains (FIG) regime that replaced the remittance basis for eligible new arrivals, and the UK’s approach shifted toward a residence-based framework for these rules.
- What changed: For eligible new residents, certain foreign income and gains can be outside UK tax for a limited period under the FIG regime.
- What didn’t: The US still generally taxes US citizens on worldwide income, and US reporting (FBAR/8938) still applies.
Which UK taxes matter most?
For most US expats, the UK taxes that matter most are income tax, National Insurance (NI), capital gains tax (CGT), and inheritance tax (IHT). These categories drive most US double–tax relief planning (FTC categories), reporting, and surprise liabilities.
| UK tax | When it applies | US expat implication |
|---|---|---|
| Income tax | Employment, self–employment, pensions, many investment categories | Often creditable for US FTC; timing differences can matter |
| National Insurance | Earnings/self–employment under UK rules | Not an income tax; totalization rules may prevent double social contributions |
| Capital gains tax | Selling assets; property is a common trigger | US also taxes worldwide gains; FX basis differences can create surprises |
| Inheritance tax | Estates, some gifts, and UK–situs assets | US estate rules are separate; treaty may matter for cross–border estates |
Personal income tax rates
The UK tax bands depend on where you live in the UK. For England, Wales, and Northern Ireland (standard bands):
| Band | Taxable income | Rate |
|---|---|---|
| Personal allowance | Up to £12,570 | 0% |
| Basic rate | £12,571 to £50,270 | 20% |
| Higher rate | £50,271 to £125,140 | 40% |
| Additional rate | Over £125,140 | 45% |
Income tax rates in Scotland
| Band | Taxable income | Scottish rate |
|---|---|---|
| Personal allowance | Up to £12,570 | 0% |
| Starter | £12,571 to £15,397 | 19% |
| Basic | £15,398 to £27,491 | 20% |
| Intermediate | £27,492 to £43,662 | 21% |
| Higher | £43,663 to £75,000 | 42% |
| Advanced | £75,001 to £125,140 | 45% |
| Top | Over £125,140 | 48% |
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, while self–employed people may pay Class 2 and Class 4 through Self Assessment.
Depending on where you work and your status, the US–UK totalization agreement can help prevent paying into both systems.
- Employee vs self–employed NI rules differ (Class 1 vs Class 2/Class 4).
- NI is not the same as income tax, and FTC treatment is not automatic.
- Self–employed NI is often paid through Self Assessment.
- Totalization: you may be able to contribute to only one system (US Social Security or UK NI) and use a certificate of coverage.
How is UK capital gains tax taxed?
UK CGT most often shows up when you sell investments or UK property. For gains made from 6 April 2025, UK residential property gains are generally taxed at 18% (within the basic rate band) and 24% (above it), after applying the annual exempt amount.
- 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 gain in one country but not the other.
Does UK inheritance tax affect me?
UK inheritance tax can matter if you hold UK assets, are a UK resident, or have UK-situs property. 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-taxed income commonly includes employment income, self-employment profits, rental income, pension income, and many investment returns.
Whether foreign income is taxed depends on UK residence and any special regimes (including the post-6 April 2025 FIG regime for eligible new residents).
Expat-relevant categories to keep 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. 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.
6-step checklist + micro timeline
- Confirm if you must file a Self Assessment (self-employed, landlord, untaxed income, HMRC notice).
- Register if needed (often due by 5 October following the end of the tax year).
- Collect UK tax documents: P60/P45, dividend/interest statements, rental summaries, pension statements.
- File your return: paper is due earlier than online.
- Pay what you owe by the payment deadline.
- Plan for payments on account if they apply (typically Jan 31 and Jul 31).
Micro timeline (typical pattern):
- Tax year ends 5 April
- Registration for first-time Self Assessment often due 5 October
- Online filing and balancing payment usually due 31 January
- Second payment on account (if applicable) due 31 July
2026 update worth knowing: From 6 April 2026, Making Tax Digital for Income Tax starts for many sole traders and landlords above the qualifying income threshold. That can add quarterly updates on top of the year-end process.
How do UK pensions affect US taxes?
UK pensions can be tax-efficient locally, but the US treatment can be complicated. Treaty language may affect how distributions (and some lump sums) are taxed, while US reporting rules can apply to accounts, investments, and underlying fund holdings.
Common US expat pitfalls with UK pensions:
- 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.
Real-life scenarios
Scenario 1: London employee choosing FTC vs FEIE
Maya is a US citizen living in London in 2025 on a UK employment contract. PAYE withheld UK income tax all year, and she has a UK savings account. On her US return, she still files Form 1040.
Because her UK taxes are substantial, using the Foreign Tax Credit often wipes out most US income tax on her salary. She still files FBAR and checks whether Form 8938 applies.
Outcome: low or no US income tax, but extra reporting.
Scenario 2: Side hustle triggers UK Self Assessment
Chris's situation is a classic US expat tax setup; he works a UK job (PAYE) but also has freelance design income and a small UK rental property. HMRC requires Self Assessment, so he files SA100 plus supplementary pages and pays any balancing amount by the UK deadline.
On the US side, he reports worldwide income; the FTC can help, but he also checks whether self-employment tax applies and whether totalization rules affect social contributions.
Outcome: more forms, but manageable with good records.
Scenario 3: ISA + pension reporting trap
Elena has a Stocks & Shares ISA and contributes to a UK workplace pension. Her ISA is tax-free in the UK, but the IRS may still tax income inside the account and may require extra reporting if the ISA holds non-US funds.
Her pension distributions later may be affected by treaty language, and some reporting positions can be nuanced.
Outcome: no immediate UK issue, but US compliance risk if she assumes “tax-free in the UK = tax-free in the US.”
What are common expat mistakes?
Most problems with US expat taxes UK aren’t about paying extra tax – they’re about missing forms.
- Skipping US filing because PAYE already withheld UK tax
- Missing FBAR or misunderstanding the $10,000 aggregate rule
- Missing Form 8938 because you filed FBAR (they’re different)
- 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)
Solve your tax question – ask professionals
If your situation includes self-employment, pensions, ISAs, or late filings, getting UK tax advice for expats alongside US filing support can prevent expensive missteps.
FAQ
In most cases, yes. US citizens and Green Card holders generally report worldwide income and may need to file Form 1040 even if they owe nothing after credits or exclusions. If you have UK bank accounts or investments, additional forms like FBAR and Form 8938 may also apply.
Being a US citizen doesn’t create UK tax on its own – UK tax is based mostly on UK residence and UK‑source income. Many employees pay UK tax through PAYE and don’t file Self Assessment, but self‑employment, rental income, or untaxed income can trigger a return.
Usually not. The Foreign Tax Credit often offsets US tax on UK‑taxed income, and the Foreign Earned Income Exclusion can exclude some earned income if you qualify. Timing differences and certain categories (like pensions or capital gains) can still create complexity.
For the 2025 tax year, the standard deadline is April 15, 2026. If you live abroad on April 15, you typically have an automatic extension to June 15, 2026 to file. You can usually extend to October 15, 2026 by filing an extension, but paying late can still trigger interest.
Late filing can lead to penalties and interest, and it can complicate future filings (especially if foreign accounts are involved). The good news: there are structured ways to catch up depending on your facts. The sooner you organize prior‑year income and account data, the easier it is to fix.
Many UK‑based expats lean toward the Foreign Tax Credit because UK tax rates can be high enough to offset US income tax on salary and other categories. FEIE can still make sense in some cases, especially for earned income, but it doesn’t cover passive income and has trade‑offs.
Yes – but not on the same income. You generally can’t claim a foreign tax credit for foreign taxes on income you excluded under FEIE. Many expats use FEIE for some earned income and FTC for other categories (like investment income), depending on the facts.
Often you don’t need to rely on treaty provisions directly, because FTC/FEIE solves most double‑tax issues. The treaty becomes more relevant for special cases like pensions, lump sums, and residency tie‑break situations, or when you take a treaty‑based position that needs disclosure.
Most people start with Form 1040 and add Form 1116 (FTC) or Form 2555 (FEIE). If you have foreign accounts, FBAR is common; if your foreign assets are higher, Form 8938 may apply. Some investment and treaty situations trigger additional forms.
If the aggregate maximum value of your non‑US financial accounts exceeded $10,000 at any point during the calendar year, FBAR filing is generally required. FBAR is filed electronically and is separate from your Form 1040. Missing it is one of the most common expat errors.
Often, yes. An ISA is tax‑advantaged in the UK, but the IRS doesn’t automatically treat it as tax‑free. You may need to report income inside the account, and the investments held in an ISA can trigger extra US reporting (especially if they include non‑US funds).
It affects what the UK taxes, and it may affect which UK forms you file, but it doesn’t remove US filing requirements for US citizens and Green Card holders. UK residence can change what UK taxes are paid (which affects FTC), and it can change what information you need to reconcile the two systems.
It depends on the type of pension and the treaty position. Some treaty provisions address pension income and social security, but US reporting and classification questions still come up. Because outcomes vary, pensions are a common reason expats get professional help.
Not automatically. UK rules and treaty language may treat certain pension lump sums differently than regular pension income, but the US treatment can still differ and may require specific reporting. If you’re planning a lump sum, it’s worth reviewing before you withdraw.
