Americans Living in the UK: Your Complete Tax Obligations Checklist

Americans living in the UK carry tax obligations in both countries at once: a US federal return reporting worldwide income every year, plus UK tax through PAYE or Self Assessment once you are UK resident. Most people owe little or nothing to the IRS after relief for UK tax, but the filing, and the reporting of accounts and investments, still has to happen on time.

What tax obligations do Americans living in the UK have?

The United States taxes on citizenship, so the obligation follows the passport rather than the address. The United Kingdom taxes on residence, so the obligation starts when you arrive and broadens once you are UK resident under the Statutory Residence Test. Neither country steps aside because the other one is taxing you. Instead, each gives credit for the other country's tax through its own rules and through the US/UK treaty.

That means two calendars, two sets of forms and two definitions of almost everything: income, residence, a pension, a tax year. The practical work is keeping them consistent, because a position taken on one return usually has to be mirrored on the other.

Question	United States	United Kingdom
Who is taxed	Citizens and green card holders, wherever they live	People who are UK resident under the Statutory Residence Test
Tax year	1 January to 31 December	6 April to 5 April
Main return	Form 1040	Self Assessment, though many employees need no return at all
Foreign account reporting	FinCEN Form 114 (FBAR) and Form 8938	No equivalent personal report
Relief for the other country's tax	Foreign Tax Credit (Form 1116) or Foreign Earned Income Exclusion (Form 2555)	Foreign Tax Credit Relief on the Self Assessment foreign pages

If you are new to the whole picture, our guide to US tax filing requirements for Americans in the UK covers the filing question on its own. This article is the wider checklist: everything both systems ask for in a normal year.

Which US tax forms do you file from the UK?

Most Americans in the UK file a Form 1040 plus two or three international schedules. The forms are driven by what you hold and where, not by how much tax you end up paying, which is why people who owe nothing still have a real filing obligation. The IRS states that the rules for filing income, estate and gift tax returns are generally the same whether you are in the United States or abroad.

Form	What triggers it	Timing
Form 1040	Income above the filing threshold for your status, or self-employment earnings above $400	15 April, automatically extended to 15 June if you live abroad
Form 2555	Foreign earned income you choose to exclude, up to $132,900 for tax year 2026	With the return
Form 1116	UK tax paid on income the US also taxes	With the return
FinCEN Form 114 (FBAR)	Foreign financial accounts exceeding $10,000 in aggregate at any time in the calendar year	15 April, automatic extension to 15 October, filed through the BSA E-Filing System
Form 8938	Specified foreign financial assets above the thresholds for taxpayers living abroad	With the return
Form 8621	Holdings in a passive foreign investment company, which covers most UK funds and investment trusts	With the return
Form 8960	Net investment income above the statutory thresholds	With the return

The two reporting forms are the ones people confuse. The FBAR applies when the combined value of your foreign accounts exceeds $10,000 at any point in the calendar year, so one day above the line makes the whole year reportable. Form 8938 has much higher thresholds for people living abroad: more than $200,000 on the last day of the tax year or more than $300,000 at any time during the year for an unmarried filer, and more than $400,000 or $600,000 respectively for a married couple filing jointly. Filing one does not replace the other. We set the two side by side in FBAR vs Form 8938.

Illustrative example: an American in Manchester has a current account peaking at £4,000, a savings account at £5,500 and a workplace pension valued at £90,000. The combined high balance crosses $10,000, so an FBAR is due covering all three accounts. The same person is nowhere near the Form 8938 thresholds that apply to taxpayers living abroad, so no Form 8938 is required that year.

Where does the UK system pick you up?

UK tax starts with residence. You are generally UK resident for a tax year if you spent 183 or more days in the UK, if your only home was in the UK for 91 days or more in a row and you stayed in it for at least 30 days of the tax year, or if you worked full-time in the UK for a 365-day period touching that year. In the year you move, the tax year is usually split into a non-resident part and a resident part under split-year treatment.

For the tax year running from 6 April 2026 to 5 April 2027, the standard Personal Allowance is £12,570, the basic rate of 20% applies to taxable income from £12,571 to £50,270, the higher rate of 40% from £50,271 to £125,140, and the additional rate of 45% above £125,140. The allowance is withdrawn by £1 for every £2 of adjusted net income above £100,000, which produces the familiar squeeze between £100,000 and £125,140.

Employees are taxed through PAYE and many never file anything. A Self Assessment return is required if, among other triggers, you were self-employed as a sole trader and earned more than £1,000, you had to pay the High Income Child Benefit Charge, or you had untaxed income such as rent, savings interest, dividends or foreign income. Americans in the UK very often have foreign income by HMRC's definition, whether that is US dividends, a US rental property or a US brokerage account, so a return is more common for this group than for the average UK employee. Our UK Self Assessment service is built around that overlap.

What are the deadlines in both systems?

The two calendars interlock rather than align. The US year runs with the calendar year; the UK year runs from 6 April. Working through them in order is the simplest way to keep a clean year.

1. 6 April — the new UK tax year begins; the previous one ended on 5 April.
2. 15 April — the US return and any US tax owed are due, and the FBAR is due on the same date.
3. 15 June — the automatic two-month extension for Americans living outside the United States. The IRS is clear that an extension is only for filing your return, not for paying it.
4. 31 July — the second payment on account for UK Self Assessment, if you make them.
5. 5 October — the date by which you must tell HMRC that you need to complete a tax return.
6. 15 October — the extended US filing deadline for those who filed Form 4868, and the final automatic FBAR deadline.
7. 31 October — HMRC must receive a paper return by 11:59pm on 31 October 2026 for the 2025 to 2026 tax year.
8. 31 January — the online return and the balancing payment for 2025 to 2026 are both due by 11:59pm on 31 January 2027.

The sequence matters for a practical reason. UK tax for a year is often not finally known until the Self Assessment return is prepared, while the US return that needs to credit that tax falls due earlier. Extending the US return to 15 October is ordinary practice for Americans in the UK rather than a sign of lateness.

The 4-year FIG regime: a UK relief that can cost an American money

On 6 April 2025 the 4-year foreign income and gains regime replaced the remittance basis, and domicile stopped being the connecting factor for this purpose. A qualifying new resident, meaning someone within their first four years of UK residence following at least ten consecutive tax years of non-UK residence, can claim relief from UK tax on qualifying foreign income and gains, and can bring that money into the UK without a further UK charge.

The catch for an American is twofold. First, claiming the regime means giving up your tax-free allowances for Income Tax and Capital Gains Tax, along with the Marriage Allowance and Blind Person's Allowance. Second, the US obligation does not move: your worldwide income sits on the Form 1040 either way. UK tax that you do not pay is UK tax you cannot credit, so relief that looks free can simply move the bill from HMRC to the IRS.

Illustrative example: an American who moves to London holding a US rental property might pay no UK tax on the rents under a FIG claim, then find the same rental profit fully taxable in the US with no UK tax available to credit, and the UK personal allowance lost against their salary as well. Modelled the other way, with no claim, UK tax paid and a US credit taken, the combined bill can be lower. The answer depends on the mix of income, which is why both routes are worth running.

Where the two systems collide

ISAs and UK funds

An ISA is tax-free in the UK and invisible to the US. Income and gains inside it are taxable on the US return, and the funds held inside a stocks and shares ISA are usually passive foreign investment companies, which pulls in Form 8621 and a default calculation designed to be unattractive. We cover the mechanics and the ways out in ISAs, PFICs and US tax.

Pensions

UK workplace pensions and SIPPs are generally protected while they grow, through the treaty rather than through UK law. Drawing on them is where the questions start, and the UK 25% tax-free lump sum is not automatically tax-free in the US. Read how the treaty treats UK pensions before taking anything out.

National Insurance and Social Security

The US/UK social security agreement stops you paying into both systems at once. Under the detached worker rule, an employee posted to the UK for a period not expected to exceed five years can stay covered by the US system, evidenced by a certificate of coverage. Self-employed Americans in the UK need the same analysis before paying either National Insurance or US self-employment tax, because the agreement decides which system applies.

Investment income

The net investment income tax adds 3.8% to investment income once modified adjusted gross income passes $200,000 for a single filer, $250,000 for a married couple filing jointly or $125,000 for someone married filing separately, and it is reported on Form 8960. It sits outside the ordinary foreign tax credit calculation, so a high-earning American in the UK can pay UK tax at 45% and still face a US charge on the same investment income. This is one of the few places where genuine double taxation arises, and it calls for planning rather than a form.

Selling your UK home

The UK usually gives full relief on a main residence. The US gives a capped exclusion and taxes the gain above it, and it measures that gain in dollars, so movement in the exchange rate between purchase and sale can create a US gain on a property that barely moved in sterling. A mortgage repaid in a stronger dollar year can produce a separate taxable gain of its own. Take advice before exchange, not after completion.

What if you have not been filing?

This is the most common question from Americans who have been in the UK for years. The usual route back is the Streamlined Foreign Offshore Procedures: delinquent or amended returns for the most recent three years for which the US due date has passed, FBARs for the most recent six years, and Form 14653 certifying that the failure was non-willful. Taxpayers who meet the non-residency requirement have the penalties waived, and many owe little or no tax once UK tax is credited.

The procedure is only available before the IRS contacts you, which is the reason not to wait. The full process is set out in our guide to the Streamlined Foreign Offshore Procedures, and the reporting side of it in our foreign income and FBAR service.

Your annual checklist

A clean year for an American in the UK follows the same sequence.

1. Fix your UK residence position for the year, including split-year treatment if you arrived or left.
2. List every financial account you hold outside the United States, with its highest balance during the calendar year, so the FBAR test can be applied properly.
3. Identify holdings that are passive foreign investment companies: funds, investment trusts and most things inside a stocks and shares ISA.
4. Decide, for that year, whether relief comes through the Foreign Tax Credit or the Foreign Earned Income Exclusion, and apply the choice consistently.
5. Prepare the US return and the UK return together, so the figures, the exchange rates and the treaty positions agree.
6. Diarise 15 April, 15 June, 15 October, 31 October and 31 January before the year starts.

US/UK Cross Border Tax is US CPAs and UK tax advisers working as one team, with offices in London, Manchester, New York and San Francisco. That structure exists for this exact problem: one team preparing both returns means the credit claimed in one country matches the tax paid in the other. If you want this handled properly, start with our page on tax obligations for Americans living in the UK, or get in touch with the details of your year.