This guide is for American citizens and green-card holders living in the United Kingdom. In brief: both countries tax you, the UK first on most income and the US on top, and for salaried people the US foreign tax credit usually cancels the US bill. The filing obligations remain, and some items, such as ISAs, UK funds and larger investment income, can create real extra tax.
Do Americans living in the UK still have to file US tax returns?
Yes. The United States taxes by citizenship, so a US citizen or green-card holder in London files on worldwide income just as someone in Ohio would[2]. The requirement depends on gross income, filing status and age, not on whether tax is owed: the return is where credits are claimed, and separate information returns about non-US accounts carry penalties even when no tax is due. Everything is reported in dollars, so sterling income and UK tax must be translated[2]. The UK, meanwhile, taxes you as a resident on worldwide income over a tax year running from 6 April to 5 April.
Does the US–UK tax treaty stop double taxation?
Partly. The 2001 US–UK income tax treaty, as amended by its 2002 protocol, contains a “saving clause” that allows the US to tax its citizens “as if this Convention had not come into effect”, so most of the treaty’s reductions and exemptions do not help a US citizen[3]. Its listed exceptions include some of the pension provisions (though not the lump-sum rule) and, above all, Article 24, relief from double taxation[3].
Article 24 sets out an order of taxation for US citizens resident in the UK. In broad terms:
- UK-source income (a UK salary, UK interest, UK rent) is taxed first by the UK; the US taxes it too but credits the UK tax.
- US-source income (dividends from US companies, US bank interest) is taxed by the UK, which only credits the US tax a non-American UK resident would pay under the treaty, such as 15% on dividends. The US then gives credit for the remaining UK tax, and the treaty “re-sources” income where necessary so that the US credit is not blocked by its own limitation rules[3].
The treaty covers US federal income taxes (not social security taxes or state taxes) and UK income tax, capital gains tax and corporation tax[3]. It does not mention Individual Savings Accounts, so ISAs get no treaty protection.
Should Americans in the UK use the foreign tax credit or the foreign earned income exclusion?
For most people living in the UK the foreign tax credit (claimed on Form 1116) produces a lower US bill and more flexibility than the foreign earned income exclusion (Form 2555), because UK income tax rates are generally at least as high as US federal rates on the same income. The exclusion can still suit particular cases, and which is better depends on your circumstances.
| Feature | Foreign tax credit (Form 1116) | Foreign earned income exclusion (Form 2555) |
|---|---|---|
| What it does | Reduces US tax dollar for dollar by UK income tax paid on foreign-source income, within limits | Removes up to $132,900 of foreign earned income from US taxable income[4] |
| Income covered | Earned and investment income, by category (general and passive)[9] | Earned income only; not pensions, dividends or interest |
| Qualifying test | UK tax paid or accrued | Tax home abroad plus bona fide residence or 330 full days abroad in 12 months[6] |
| Unused amounts | Carried back 1 year and forward 10[8] | Lost |
| Effect on other income | None | Remaining income is taxed at the rates that would apply without the exclusion (“stacking”)[1] |
| Refundable child tax credit | Available if you qualify (refundable portion up to $1,700 per child for 2026)[4] | Not available: filing Form 2555 rules out the additional child tax credit[10] |
| Switching | Year by year | Once revoked, re-electing within 5 tax years needs IRS approval[7] |
The practical difference is the carry-forward. A higher-rate UK taxpayer usually pays more UK tax on a salary than the US would charge; with the credit, the surplus can be carried forward for up to ten years against later foreign-source income in the same category[8]. With the exclusion, UK tax on the excluded salary cannot be credited at all[1].
Timing also matters because the UK and US tax years do not match. A cash-basis US taxpayer can elect to claim credits in the year the tax accrues by ticking the “accrued” box on a timely filed original return (not an amended one); accrued taxes generally use the average exchange rate for the year, while taxes claimed when paid use the rate on the payment date[9].
When does a US citizen in the UK end up paying tax to both countries?
Extra tax arises where the UK taxes lightly or not at all, or where US rules have no UK equivalent: the credit only removes US tax up to the UK tax on the same income.
| Item | UK treatment | US treatment | Result |
|---|---|---|---|
| ISA interest, dividends and gains | Tax-free | Taxable; no treaty relief | US tax with no UK credit to offset it |
| UK funds (unit trusts, OEICs, most UK-listed ETFs and investment trusts) | Ordinary fund taxation | Usually passive foreign investment companies (PFICs) | Punitive default US regime and Form 8621 reporting |
| Investment income above $200,000 / $250,000 of modified AGI | Income tax and CGT | 3.8% net investment income tax on top | Foreign tax credits cannot offset it[11] |
| Premium Bond prizes | Tax-free | Taxable as income | US tax only |
| Sale of a UK home | Usually exempt as main residence | Gain above the home-sale exclusion is taxable, measured in dollars | Possible US tax only |
| Capital gains in low-UK-tax years | £3,000 annual exempt amount, then 18% or 24%[18] | 0%, 15% or 20%, measured in dollars | Differences in timing and currency can leave residual US tax |
| Years with little UK tax (career break, early retirement) | Personal allowance of £12,570[15] | Standard deduction $16,100 single / $32,200 joint[5] | US tax may exceed UK tax on some income |
The net investment income tax deserves particular attention. It is a 3.8% tax on investment income for those with modified adjusted gross income above $200,000 (single) or $250,000 (married filing jointly), and the thresholds are not indexed for inflation[11]. Treasury regulations say foreign tax credits are not allowed against it[12]. Some taxpayers have argued that treaties require a credit. On 31 August 2026 the US Court of Appeals for the Federal Circuit held in Christensen v. United States (French treaty) and, in a separate opinion the same day, Estate of Bruyea v. United States (Canadian treaty), that neither treaty allows a credit against it, because each treaty grants credit only in accordance with, and subject to the limitations of, US law[13][29]. The UK treaty was not before the court, but its US credit provision opens with the same words[3], so claims based on it face the same difficulty. A deduction for foreign taxes against net investment income remains possible in some cases[11].
ISAs and UK funds are the largest practical trap; see ISAs, UK funds and PFIC rules for Americans. Pensions are treated differently because some of the treaty’s pension provisions survive the saving clause: growth inside a pension is taxed only when paid out, and social security is taxed only in the country of residence. Lump sums are the exception. HMRC’s manuals say the US can tax lump sums received by US citizens from UK schemes[27] and, since March 2025, that the UK can tax lump sums from US pensions paid to UK residents despite the treaty’s lump-sum article, with credit for US tax[28]; the second view has been questioned by practitioners. See UK pensions for US persons and US retirement accounts when you live in the UK. Currency adds a layer the UK does not see: the US measures gains in dollars, so an asset sold at a sterling loss can show a dollar gain. Our guide to GBP/USD currency risk explains the rules.
How does the UK decide whether an American is UK resident?
The UK uses the statutory residence test, applied tax year by tax year. You are automatically UK resident if, for example, you spend 183 days or more in the UK in the tax year, or your only home is in the UK for at least 91 consecutive days and you are there on at least 30 days, or you work full-time in the UK for a 365-day period[19].
You are automatically non-resident if you spend fewer than 16 days in the UK (46 days if you were not UK resident in any of the previous three tax years), or you work full-time abroad and spend fewer than 91 days in the UK, with no more than 30 of them working[19]. If neither set of automatic tests settles the matter, the “sufficient ties” test counts days against ties such as family, accommodation, work and time spent in the UK in earlier years. HMRC’s detailed guidance is set out in RDR3[20].
Domicile no longer drives UK income tax: from 6 April 2025 the remittance basis was replaced by a residence-based regime[21], so long-term American residents are taxed in the UK on worldwide income and gains as they arise.
What is the UK’s four-year FIG regime, and does it help Americans?
The foreign income and gains (FIG) regime lets a new UK resident who has been non-resident for at least 10 consecutive tax years claim UK tax relief on foreign income and gains for their first four tax years of residence[21]. It does not cover foreign employment income, and anyone who claims it loses the income tax personal allowance and the capital gains tax annual exempt amount for that year[21].
For a newly arrived American, the regime can take US dividends, interest and gains out of UK tax for up to four years. They remain taxable in the US, so the household pays US tax only on them. That can be lower than otherwise, because UK rates on dividends (35.75% for higher-rate taxpayers from April 2026) and gains (24%) are above US long-term rates for many people[15][18].
The regime is not automatically worthwhile. Losing the £12,570 personal allowance costs a basic-rate taxpayer about £2,500 and a higher-rate taxpayer about £5,000 a year. The claim is made through Self Assessment each year and you can choose which foreign income and gains to include[21]; whether it helps is a calculation to run, not a rule of thumb. See also Moving between the UK and the US.
Which forms do Americans in the UK file, and when?
A typical employed American in the UK files a US Form 1040 with Form 1116 (or Form 2555), an FBAR, often Form 8938, and a UK Self Assessment return if HMRC requires one. The table sets out the main items for the 2026 US year and the 2025/26 UK year.
| Filing | What it covers | Threshold or trigger | Deadline |
|---|---|---|---|
| Form 1040 | US income tax on worldwide income | Gross income filing thresholds | 15 April; automatic extension to 15 June if living abroad (interest from 15 April); to 15 October with Form 4868[1] |
| Form 1116 | Foreign tax credit | Claiming credit for UK tax | With Form 1040 |
| Form 2555 | Foreign earned income and housing exclusion | If electing the exclusion | With Form 1040 (Form 2350 can extend while you meet the test)[1] |
| FinCEN Form 114 (FBAR) | Non-US financial accounts, including ISAs and pensions where reportable | Aggregate above $10,000 at any time in the year | 15 April, automatic extension to 15 October[14] |
| Form 8938 | Specified foreign financial assets | Living abroad: above $200,000 at year-end or $300,000 at any time (single); $400,000 / $600,000 (joint)[14] | With Form 1040 |
| Form 8621 | Each PFIC holding | See the ISA and PFIC guide | With Form 1040 |
| Form 3520 | Foreign trusts, and gifts or bequests above $100,000 from non-US persons | When triggered[2] | With Form 1040 |
| UK Self Assessment | UK income and gains, including foreign income | Register by 5 October after the tax year if you need to file | Paper 31 October 2026; online and payment 31 January 2027 for 2025/26[22] |
Penalties for the information returns are significant: $10,000 for failing to file Form 8938, rising to as much as $60,000 for continued failure; non-wilful FBAR penalties up to $10,000 per violation (inflation-adjusted), and wilful ones the greater of $100,000 or half the balance[14]. Many Americans in the UK also need a Self Assessment return because of foreign or untaxed investment income, even when PAYE covers their salary.
Can a US state still tax an American who lives in the UK?
Possibly. States set their own residence rules, and some continue to treat a person as resident while they remain domiciled there, even when they live abroad. The treaty does not cover state taxes, and US federal foreign tax credits do not flow through to state returns automatically.
California is a well-known example. Its guidance treats a California-domiciled person who is abroad under an employment-related contract for at least 546 consecutive days as non-resident, but not if they have intangible income (such as investment income) above $200,000 in any tax year of the contract, or if the principal purpose of the absence is to avoid tax; return visits of up to 45 days a year are treated as temporary[24]. Other states apply different tests.
Do Americans in the UK pay US Social Security tax as well as National Insurance?
Usually not both. The US–UK social security (totalisation) agreement assigns coverage to one country. An employee sent temporarily from the US to the UK can stay in the US system for up to five years; self-employed people are covered by the country where they live, so a self-employed American resident in the UK pays UK National Insurance and should attach a certificate of coverage to each US return to show exemption from US self-employment tax[23].
For 2026/27 employee National Insurance is 8% on earnings between £12,570 and £50,270 and 2% above[17]. The IRS allows no credit or deduction for social security taxes paid to a country with which the US has an agreement[9], so National Insurance never reduces the US bill.
From 6 April 2026 the UK removed access to voluntary Class 2 contributions for people abroad and restricted new applications for voluntary Class 3 contributions to those with at least 10 continuous years of UK residence or 10 qualifying years of contributions[16]. See Social Security and the UK State Pension for how benefits interact.
Does renouncing US citizenship end US tax?
It ends US taxation of future non-US income, but it is irreversible and has tax consequences of its own. The State Department cut the fee for processing a renunciation from $2,350 to $450 with effect from 13 April 2026[26].
A former citizen is a “covered expatriate”, and may owe an exit tax on unrealised gains, if their net worth is $2 million or more, if their average annual net US income tax over the previous five years exceeds a threshold ($211,000 for 2026), or if they cannot certify five years of US tax compliance[25][4]. For 2026 the first $910,000 of deemed gain is excluded[4]. Every expatriate files Form 8854, with a $10,000 penalty for failing to do so[25]. The decision has personal and legal dimensions well beyond tax and needs specialist advice.
Worked example: one year of tax for an American household in the UK (computed in Edale’s planner)
Fictional household, for illustration only. Alex (50) is a US citizen earning a salary of about £94,000; Sam (48) earns about £38,000. Both are UK resident. They hold a $200,000 US brokerage account, a Stocks and Shares ISA, SIPPs and a UK general investment account. The planner computed the 2026 year, applying UK income tax and National Insurance, Alex’s US federal income tax on worldwide income, and the foreign tax credit. Figures are rounded, depend on the assumptions stated, and are not a prediction or guarantee of any real household’s tax.
| Item | Amount |
|---|---|
| UK income tax (household) | about £28,990 |
| UK National Insurance (household) | about £5,950 |
| Alex’s US federal income tax before credits (sterling equivalent) | about £15,250 |
| Foreign tax credit used | about £15,250 |
| US tax actually paid | £0 |
| Total tax paid | about £34,940 |
| Total tax if neither partner were a US person | about £34,940 |
The result is the one most salaried Americans in Britain see: Alex’s US liability of about £15,250 is computed and then fully offset by credit for UK tax, so the household pays exactly what a British household would. The reason is the level of UK tax on Alex’s salary. As a simple illustration of our own, not taken from the planner, UK income tax on a £94,000 salary at 2026/27 rates, before pension contributions, is about £25,000: 20% on the first £37,700 above the personal allowance and 40% on the rest[15]. That is well above the US tax on the same income, and the excess is available to carry forward, within limits, for ten years[8]. National Insurance plays no part in the credit.
The headline hides two things. Alex still files Form 1040 with Form 1116, an FBAR and probably Form 8938, and the ISA’s income is taxable in the US; UK funds inside it would be PFICs. And the picture changes in years with a pension lump sum, a property sale, a large dollar-measured gain, investment income above the net investment income tax threshold, or early retirement, when UK tax falls and the US top-up can become real. The planner recalculates both systems for every year of the plan, which is where those differences show up.
How the Edale Wealth Hub helps
For an American in Britain the answer depends on how two tax systems interact every year, so the Edale Wealth Hub calculates both side by side.
- Both tax systems, year by year. Edale’s planner applies UK income tax (including Scottish rates), National Insurance, capital gains tax and the personal-allowance taper, together with US federal income tax, payroll taxes, the net investment income tax and long-term capital gains rates. For US persons it applies foreign tax credits and treaty treatment, so the plan shows what the household actually keeps, not a UK-only figure.
- Tax rules over time. Thresholds can be held at today’s levels or applied year by year as legislated or announced, such as the UK savings and property rate rises from April 2027.
- Both sets of accounts in one plan. ISAs, SIPPs, workplace and defined-benefit pensions, general accounts and investment bonds sit alongside 401(k)s, IRAs, Roth IRAs, brokerage accounts and Social Security, in any mix of currencies. The planner flags non-US funds held by US persons that are likely to be PFICs.
- What-ifs. Early retirement, a move between the UK and the US, a market fall or a first death can be tested to see when the US top-up stops being zero.
- Portal reporting. For accounts linked by the adviser (currently Interactive Brokers UK and US), clients see capital gains, dividends and interest in pounds and dollars, and a 1099-style US tax summary (not a Form 1099) showing foreign tax and Form 8949 detail.
There are limits. Edale does not prepare US tax returns and is not a US-registered investment adviser; the Wealth Hub’s tax outputs are summaries to share with your accountant or tax preparer, not returns or IRS forms. Results depend on the information and assumptions entered. If you would like to see how the two systems apply to your own household, you can arrange a conversation or read more about Edale’s planner and our complete guide to US–UK wealth planning.
Frequently asked questions
Do I have to file a US tax return if I owe no US tax?
Usually yes. The filing requirement depends on gross worldwide income, filing status and age, not on the tax finally due. The return is where foreign tax credits are claimed, and separate FBAR and Form 8938 reporting of non-US accounts can apply, with penalties for missing them even when no tax is owed.
Is it better to claim the foreign tax credit or the foreign earned income exclusion?
For many UK residents the foreign tax credit works better because UK income tax is often higher than US tax on the same salary, and unused credits can be carried forward for ten years. The exclusion covers only earned income, up to $132,900 for 2026, and rules out the refundable child tax credit. The right choice depends on your circumstances.
Can I use UK tax to offset the 3.8% net investment income tax?
Under current US rules, no. Treasury regulations do not allow foreign tax credits against the net investment income tax, and on 31 August 2026 the Federal Circuit rejected treaty-based claims under the French and Canadian treaties. The UK treaty was not tested in that case. A deduction for foreign taxes may reduce net investment income in some situations.
Are ISAs tax-free for Americans living in the UK?
Only in the UK. The US does not recognise ISAs, and the treaty does not mention them, so interest, dividends and gains are taxable on your US return with no UK tax to credit against them. UK funds held inside an ISA are usually PFICs, which brings a harsher default US regime and extra reporting. Individual shares avoid the PFIC problem but not US tax.
When are US tax returns due for Americans abroad?
If you live outside the US on the regular due date you get an automatic extension to 15 June, and can extend to 15 October with Form 4868. Interest on any tax owed runs from 15 April, so paying an estimate by then limits the cost. The FBAR is due on 15 April with an automatic extension to 15 October.
Does the UK four-year FIG regime help US citizens?
It can. New UK residents who were non-resident for the previous 10 tax years can claim UK relief on foreign income and gains, such as US dividends, for up to four years. The US still taxes that income, and claiming costs the personal allowance and CGT exempt amount for the year, so it depends on the numbers.
Do I pay both US Social Security tax and UK National Insurance?
Normally only one. Under the US–UK totalisation agreement, employees working for a UK employer pay National Insurance, employees seconded from the US can stay in the US system for up to five years, and self-employed people pay into the country where they live. A certificate of coverage evidences the exemption. National Insurance cannot be credited against US income tax.
Can a US state tax me while I live in the UK?
It can, depending on the state. Some states continue to treat people as resident while they remain domiciled there. California, for instance, treats a domiciliary working abroad for 546 consecutive days under an employment contract as non-resident, unless intangible income exceeds $200,000 in a year or the absence is mainly to avoid tax. The treaty does not cover state taxes.
Sources
- IRS — Publication 54, Tax Guide for U.S. Citizens and Resident Aliens Abroad (accessed September 2026)
- IRS — U.S. citizens and resident aliens abroad: filing requirements (accessed September 2026)
- GOV.UK — 2001 UK–USA Double Taxation Convention as amended by the 2002 protocol (accessed September 2026)
- IRS — Revenue Procedure 2025-32 (2026 inflation adjustments) (accessed September 2026)
- IRS — Tax inflation adjustments for tax year 2026, including amendments from the One, Big, Beautiful Bill (accessed September 2026)
- IRS — Foreign earned income exclusion: physical presence test (accessed September 2026)
- IRS — Revoking your choice to exclude foreign earned income (accessed September 2026)
- IRS — Topic no. 856, Foreign tax credit (accessed September 2026)
- IRS — Publication 514, Foreign Tax Credit for Individuals (accessed September 2026)
- IRS — Instructions for Schedule 8812 (Form 1040) (accessed September 2026)
- IRS — Questions and answers on the net investment income tax (accessed September 2026)
- eCFR — 26 CFR 1.1411-1, General rules (net investment income tax) (accessed September 2026)
- US Court of Appeals for the Federal Circuit — Christensen v. United States, opinion of 31 August 2026 (accessed September 2026)
- IRS — Comparison of Form 8938 and FBAR requirements (accessed September 2026)
- GOV.UK — Income Tax rates and allowances for current and previous tax years (accessed September 2026)
- HM Treasury and HMRC — Budget 2025: Overview of tax legislation and rates (accessed September 2026)
- HMRC — Rates and thresholds for employers 2026 to 2027 (accessed September 2026)
- GOV.UK — Capital Gains Tax rates (accessed September 2026)
- GOV.UK — Tax on foreign income: residence (accessed September 2026)
- HMRC — RDR3: Statutory Residence Test guidance note (accessed September 2026)
- HMRC — Check if you can claim the 4-year foreign income and gains regime (accessed September 2026)
- GOV.UK — Self Assessment tax returns: deadlines (accessed September 2026)
- Social Security Administration — U.S.–United Kingdom totalization agreement (accessed September 2026)
- California Franchise Tax Board — Publication 1031 (2025), Guidelines for Determining Resident Status (accessed September 2026)
- IRS — Expatriation tax (accessed September 2026)
- Federal Register — Schedule of Fees for Consular Services: Certificate of Loss of Nationality fee (final rule, 13 March 2026) (accessed September 2026)
- HMRC — Double Taxation Relief Manual DT19853: United States of America, notes (accessed September 2026)
- HMRC — International Manual INTM163160: pensions, lump sums (accessed September 2026)
- US Court of Appeals for the Federal Circuit — Estate of Bruyea v. United States, No. 25-1563, opinion of 31 August 2026 (via Justia) (accessed September 2026)