Tax residence in the UK for U.S. citizens and green card holders

The UK decides residence under the Statutory Residence Test: automatic overseas and UK tests first, then the number of UK ties combined with the days you spend in the UK. The UK tax year runs from 6 April to 5 April. U.S. citizens remain taxable in the United States; the U.S.–UK treaty settles dual residence and double taxation.

Check your status: United States and United Kingdom

Free, no sign-up, about 3 minutes. Conclusion under U.S. law, compared with the law of the United Kingdom and the tax treaty.

When United Kingdom treats you as a tax resident

The UK determines residence under its own Statutory Residence Test (SRT) and for its own tax year — 6 April to 5 April — not the calendar year used in the United States.

You spent 183 days or more in the UK in the UK tax year — you are automatically UK resident.
Your only home is in the UK (no home abroad, including in the U.S., where you spent 30+ days) — under the home test you are UK resident.
Full-time work in the UK for a 365-day period — you are UK resident.
Your UK days combined with your UK ties reach the sufficient ties threshold — you are UK resident even with fewer than 183 days.

When you are a nonresident

You spent fewer days in the UK than any UK test requires (16 or 46) — you are automatically not UK resident.
Full-time work abroad and fewer than 91 days in the UK — under the automatic overseas test you are not UK resident.
Under the sufficient ties test you have too few UK ties for your number of days — you are not UK resident.

Where the rules of the United Kingdom clash with U.S. tax rules

Collision: U.S. citizens stay taxable in the United States even as UK residents. The UK taxes you as a resident on worldwide income. The United States taxes its citizens on worldwide income regardless of where they live. Even if the treaty tie-breaker makes you a UK resident, the saving clause (Art. 1(4)) lets the United States tax you as if the treaty did not exist; Art. 24 is excepted from the saving clause (Art. 1(5)). Double taxation is relieved under Art. 24(6): the UK credits U.S. tax only on U.S.-source income and only up to the tax a non-citizen would pay; the United States credits UK income tax and capital gains tax, re-sourcing income to the UK where needed.
Collision: the UK treats you as resident with fewer than 183 days. The SRT makes you UK resident with fewer than 183 days — through the home test, full-time work in the UK or the sufficient ties test (family, accommodation, work, previous years). If you are also a U.S. resident (citizen, green card or substantial presence), the tie-breaker in Art. 4(4) decides treaty residence: permanent home, then centre of vital interests, then habitual abode, then nationality. For U.S. citizens the saving clause (Art. 1(4)) keeps U.S. tax in place regardless.
Collision: after moving back to the U.S. the UK may still treat you as resident. If you were UK resident in any of the three previous UK tax years, 16 days and 4 ties (or 46 days and 3 ties) are enough to remain UK resident. If you are a U.S. resident at the same time, Art. 4(4) of the treaty decides.

What else to know

Different tax years. The United States uses the calendar year; the UK tax year runs from 6 April to 5 April. One stay can fall into different «years» in each country: for example, October to June can be more than 183 days in one UK tax year but fewer than 183 days in each of two U.S. calendar years. The treaty's 183-day employment test uses any twelve-month period commencing or ending in the taxable year or year of assessment.
Treaty residence test for U.S. citizens and green-card holders. For treaty purposes a U.S. citizen or green-card holder counts as a U.S. resident only with a substantial presence, permanent home or habitual abode in the United States (Art. 4(2)). If you have none of these, you are not a dual resident under the treaty — the UK is your treaty residence, while the United States still taxes citizens under the saving clause.
Year of arrival or departure: the UK may split the tax year. Under specific conditions (moving your home, starting or ending full-time work) the UK tax year is split into two parts and you are taxed as a non-resident for the overseas part. U.S. status is determined per calendar year under U.S. rules.
FIG regime for new UK residents. If you were not UK resident for at least 10 years before arriving, you can claim the FIG regime for up to the first 4 tax years of UK residence: qualifying foreign income and gains are not taxed in the UK, but you lose the income tax and CGT tax-free allowances, and foreign employment income is not covered. For U.S. citizens this income remains taxable in the United States, and with no UK tax on it there is no UK tax to credit against U.S. tax.
Working in the UK for a U.S. employer. Employment income is sourced where you physically work. If you are a U.S. resident under the treaty, the UK does not tax your pay for UK work if you are present not more than 183 days in any twelve-month period commencing or ending in the taxable year or year of assessment, the employer is not UK resident and the pay is not borne by a UK permanent establishment (Art. 14(2)). Otherwise the UK taxes the pay for UK work days and the United States gives a credit.
Social security: U.S.–UK totalization agreement. The U.S.–UK social security agreement (coverage provisions in effect since 1 January 1985) prevents paying both U.S. Social Security/self-employment tax and UK National Insurance on the same work. Generally you are covered where you work; an employee temporarily sent by the same employer (generally for a period not expected to exceed 5 years) stays in the home system; self-employed persons are covered by their country of residence. Exemption from U.S. contributions requires a certificate of coverage.

How dual residence is resolved

If both countries treat you as a resident, Art. 4(4) of the treaty applies: Convention between the Government of the United States of America and the Government of the United Kingdom of Great Britain and Northern Ireland for the avoidance of double taxation and the prevention of fiscal evasion with respect to taxes on income and on capital gains (signed 24 July 2001, amended by the Protocol of 19 July 2002). The tests are applied in order — permanent home, center of vital interests, habitual abode, nationality, and finally mutual agreement between the tax authorities. U.S. citizens remain taxable in the United States under the saving clause.

Terms you will come across in the UK

Statutory Residence Test (SRT): the UK test of tax residence: automatic tests and sufficient ties
tax year: 6 April to 5 April
UK ties: family, accommodation, work, 90-day and country ties
split year treatment: splitting the year of arrival or departure
FIG regime: 4-year foreign income and gains regime for new residents (from 6 April 2025)
HMRC: HM Revenue & Customs

Questions

I am a U.S. citizen — do I still pay U.S. tax if I live in the UK?

Yes. The United States taxes its citizens on worldwide income wherever they live, and the treaty keeps that right through the saving clause (Art. 1(4)). You file Form 1040 every year; double taxation is relieved mainly by the foreign tax credit (Form 1116) or the foreign earned income exclusion (Form 2555), plus the treaty's relief article (Art. 24).

Which treaty applies between the U.S. and the UK?

The Convention signed on 24 July 2001, with the Protocol of 19 July 2002, in force since 31 March 2003. The individual tie-breaker is in Art. 4(4); a U.S. citizen or green card holder counts as a U.S. resident for the treaty only with substantial presence, a permanent home or a habitual abode in the U.S. (Art. 4(2)).

What is the UK FIG regime?

From 6 April 2025 the remittance basis was replaced by a 4-year foreign income and gains (FIG) regime for people who were not UK resident for at least 10 years before arriving. U.S. citizens can use it, but the United States still taxes that income — and with no UK tax on it there is nothing to credit.

Sources

Legislation and official guidance

Finance Act 2013, Sch. 45 (Statutory Residence Test) — You are UK resident if you meet at least one automatic UK test and none of the automatic overseas tests, or if you meet the sufficient ties test. The automatic overseas tests take priority.
Income Tax Act 2007, s. 4(3) — The UK tax year runs from 6 April to the following 5 April.
HMRC RDR3 — Statutory Residence Test guidance — HMRC's official guidance on the Statutory Residence Test.
Sch. 45, paras 12–14 — Automatically non-resident: fewer than 16 days in the UK (if UK resident in any of the 3 previous tax years), fewer than 46 days (if not), or full-time work abroad with fewer than 91 days in the UK and fewer than 31 UK work days.
Sch. 45, paras 22–23 — A day counts if you are in the UK at midnight; transit days do not count; up to 60 days spent in the UK because of exceptional circumstances (war, natural disaster) can be disregarded.
Sch. 45, para 7 — Automatically UK resident: at least 183 days in the UK in the tax year.
Sch. 45, paras 8, 25 — Home test: a UK home where you spent at least 30 days, and no overseas home where you spent at least 30 days (assessed within a 91-day period).
Sch. 45, para 9 — Full-time work in the UK for a 365-day period: on average at least 35 hours a week, with more than 75% of working days in the UK.
Sch. 45, paras 17–19, 31–38 — Sufficient ties test: arrivers — 46–90 days and 4 ties, 91–120 days and ≥3, ≥121 days and ≥2; leavers (UK resident in 1 of the 3 previous years) — 16–45 days and ≥4, 46–90 and ≥3, 91–120 and ≥2, ≥121 and ≥1. Ties: family, accommodation, work, 90-day, country.
Art. 14(2) U.S.–UK Convention — Employment income for work done in the other State is taxable only in the State of residence if the employee is present there not more than 183 days in aggregate in any twelve-month period commencing or ending in the taxable year or year of assessment concerned, the pay is not paid by or on behalf of an employer resident in the other State, and is not borne by a permanent establishment there.
Art. 1(4) U.S.–UK Convention (saving clause) — Notwithstanding any provision of the Convention except Art. 1(5), a Contracting State may tax its residents (as determined under Art. 4) and, by reason of citizenship, its citizens as if the Convention had not come into effect.
Art. 1(5) U.S.–UK Convention — Exceptions to the saving clause include Art. 9(2), certain pension rules (Art. 17, Art. 18(1) and (5)) and Articles 24 (relief from double taxation), 25 (non-discrimination) and 26 (mutual agreement procedure).
Art. 24(4)–(6) U.S.–UK Convention — The UK credits U.S. tax on income from U.S. sources against UK tax (Art. 24(4)–(5)). For a U.S. citizen resident in the UK (Art. 24(6)): the UK need not credit U.S. tax on non-U.S.-source income; on U.S.-source income the UK credit is limited to the U.S. tax a non-citizen UK resident would pay; the United States credits UK income tax and capital gains tax, and income is re-sourced to the UK to the extent needed to relieve double taxation.
Art. 4(4) U.S.–UK Convention — Dual-resident individuals: (a) permanent home; if in both States — centre of vital interests; (b) if that cannot be determined, or no permanent home in either State — habitual abode; (c) habitual abode in both or neither — nationality; (d) national of both or neither — competent authorities by mutual agreement.
Art. 4(2) U.S.–UK Convention — A U.S. citizen or green-card holder is a U.S. resident for treaty purposes only if he or she has a substantial presence, permanent home or habitual abode in the United States and is not a resident of a third State under a UK treaty with that State.
Sch. 45, Part 3 (paras 44–51); HMRC RFIG21010 — In the year of arrival or departure the UK tax year may, under specific conditions, be split: the overseas part is taxed as for a non-resident. It is not elective — it applies automatically if the conditions are met.
Finance Act 2025, s. 37; ITTOIA 2005 ss. 845A–845J; GOV.UK «Check if you can claim the 4-year foreign income and gains regime» (published 6 April 2025) — From 6 April 2025 the 4-year foreign income and gains (FIG) regime replaced the remittance basis. Available for at most 4 consecutive tax years from the start of UK residence, after at least 10 years of non-UK residence; claimed on the Self Assessment return; claimants lose the income tax and CGT tax-free allowances. Foreign earnings and specific employment income are not eligible.
SSA POMS GN 01701.005 — International Social Security (Totalization) Agreements — U.S.–UK agreement effective 1 January 1985 (coverage provisions) and 1 January 1988 (benefit provisions).
SSA — Totalization Agreement with United Kingdom — Self-employed workers who reside in the U.S. are covered by U.S. Social Security, those residing in the UK by UK National Insurance; employers and self-employed workers must request a certificate of coverage (from HMRC for UK coverage) to be exempt from U.S. Social Security contributions.
SSA, Social Security Bulletin Vol. 78 No. 4 (2018), «Social Security Totalization Agreements» — General rule: coverage where you work (territoriality); exception: a worker temporarily sent abroad by the same employer, generally for a period not expected to exceed 5 years, stays covered by the home country; self-employment is generally covered by the country of residence.
Art. 4(4)(a) of the Convention — A dual resident is deemed a resident only of the State in which he has a permanent home available to him; if he has a permanent home in both States, only of the State with which his personal and economic relations are closer (centre of vital interests).
Art. 4(2) of the Convention — A U.S. citizen or green-card holder is a U.S. resident for treaty purposes only if he or she has a substantial presence, permanent home or habitual abode in the United States and is not a resident of a third State under that State's treaty with the UK.
Art. 4(4)(b) of the Convention — If you have no permanent home available in either State, the treaty goes straight to habitual abode (the centre of vital interests step applies only where there is a home in both States).
Art. 4(4)(c), (d) of the Convention — Habitual abode in both States or in neither — resident only of the State of which you are a national; national of both or neither — the competent authorities shall endeavour to settle the question by mutual agreement.

Case law

Court of Appeal (England and Wales), A Taxpayer v HMRC [2025] EWCA Civ 106, 2025-02-13 — Moral obligations (caring for the children of a seriously ill relative) can be taken into account in deciding whether circumstances are exceptional for disregarding days under para 22(4); a person with 50 days was held not UK resident against a threshold of 45.
First-tier Tribunal (Tax Chamber), Michael Parker v HMRC [2026] UKFTT 652 (TC), 2026-05-01 — Three days were treated as transit and one as exceptional circumstances; with 89 remaining UK days the taxpayer met the full-time work abroad test and was not UK resident.

Updated 2026-11-04. The result is for information only and is not tax or legal advice. Tax authorities and courts may interpret the rules differently, including because of circumstances not covered here, and the law changes. Consult a qualified adviser before making decisions.

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