| Updated | November 2026, UK tax year 2026/27, US tax year 2026 |
| Leaving the UK | statutory residence test, split year, notice on P85 or SA109 |
| US residence | green card or substantial presence test (31 days in the year and 183 weighted days over three years) |
| UK pension | periodic payments taxable in the country of residence, lump sums only in the UK |
| Return trap | five years under UK law, a six-year reservation for gains in the treaty |
| Inheritance tax | UK-US convention since 1979; long-term UK residence can carry on for up to 10 years |
Leaving the UK
Whatever your passport, HMRC only cares whether you are UK resident under the statutory residence test. The test looks at each tax year on its own. Go to the US for a full-time job and the third automatic overseas test makes you non-resident: full-time work abroad and fewer than 91 days in the UK. Move without a job and you need fewer than 16 days in the UK or few enough ties.
In the year you leave, split year treatment can divide the year: case 1 for starting full-time work abroad, case 2 for the partner who moves with you, case 3 for anyone giving up their UK home. You tell HMRC on P85 or on the SA109 residence pages. Everything in detail is in leaving the UK.
When you become taxable in the US
The US side asks differently. With a green card you are resident for US federal tax once you are a lawful permanent resident in the calendar year. Without one, the substantial presence test decides: at least 31 days in the current year and 183 days over three years, counting the current year in full, the previous year at a third and the year before at a sixth.
A US resident is taxed in the US on worldwide income, just like a citizen. In the year of the move, US residence often starts mid-year, for a green card holder for instance on the first day in the US as a lawful permanent resident. Such dual-status years are the classic source of errors. Mount Bonnell explains the US tax return in your moving year, and its guide to moving from the UK to the USA covers the American side of the move.
Five years in the UK, six years in the treaty
The temporary non-residence rules apply to a move to the US too. If you were solely UK resident in four of the seven tax years before the year you leave and come back within five years, HMRC taxes, in the year you return, among other things capital gains, certain pension payments and lump sums, and distributions from close companies from your time in the US. You are only safe after five years and one day.
The treaty leaves the UK room for this. In principle only the country of residence may tax capital gains. But Article 13(6) lets the UK tax, under its own law, gains of a person who was UK resident within the six years before the disposal. If you are taxed in the US in the meantime as well, the treaty's credit rules take over.
UK pension and ISA under the treaty
Periodic pensions are in principle taxable only in the country of residence under Article 17(1), so in the US after the move. What a UK resident could receive tax-free from a UK pension stays tax-free in the US too. Lump sums from a UK pension scheme, on the other hand, may be taxed only by the UK (Article 17(2)). Income inside the UK scheme is taxed in the US only on payment (Article 18(1)). You claim UK relief on the form for US residents; the US authority certifies your residence.
Social security benefits are taxable only in the country of residence under Article 17(3). The UK generally does not tax non-residents on the State Pension anyway. Careful: for US citizens and green card holders the saving clause shifts some of these rules; the US side settles that for your case.
You may keep your ISA; as a non-resident you can no longer pay in, and you tell the provider you have left. But the exemption is a UK rule, and the treaty does not name ISAs. As a US resident you will also meet the PFIC rules for foreign funds. How that looks for Americans in the UK is in US citizens in the UK; after the move the position is the same.
Keeping UK property
A let flat in the UK stays taxable in the UK. If you live abroad for six months or more a year, you are a non-resident landlord, and the agent or tenant deducts tax unless HMRC approves gross payment. Budget 2026 of 28 October 2026 announces rates of 24, 44 and 49 percent on property income in England, Wales and Northern Ireland from 6 April 2027; that becomes law with the Finance Bill 2026-27.
On a sale the UK keeps the taxing right, under the treaty too, which allows gains on land to be taxed where the land is. You report the sale within 60 days of completion, even with no tax due. More in selling UK property as a non-resident.
Inheritance tax and the 1979 convention
If you were UK resident in 10 of the last 20 tax years, you take long-term UK resident status with you; it can carry on for up to ten tax years after you leave. For that long, assets in the US can fall into UK inheritance tax too. UK assets such as property or a UK account stay in the net anyway, at 40 percent above the £325,000 nil-rate band.
For overlaps there is the UK-US estate and gift tax convention, in force since 11 November 1979. The country of (fiscal) domicile may tax everything, the other only certain assets such as land in its territory. Since April 2025 a long-term UK resident counts as UK-domiciled for it.
Taking your own UK company to the US
Your limited company does not move with you. A company incorporated in the UK is in principle UK resident under UK law, even if you run it from Texas. The US, by contrast, decides a company's residence by its place of incorporation alone. If a company is ever treated as resident in both states, the two tax authorities settle it between them.
Dividends from your UK company are mostly unproblematic in the UK for you as a non-resident: HMRC limits the tax on a non-resident's UK dividends and interest to whatever was deducted at source. But mind the timing: distributions from your close company fall under the five-year rule if you come back. How the US taxes you as a shareholder of a UK company is a US question; Mount Bonnell's US tax consultation is the place for it.
Frequently asked questions about moving from the UK to the US
When do I stop being taxable in the UK?
The statutory residence test decides for each UK tax year. Split year treatment can divide the year you leave. UK income such as rent stays taxable in the UK all the same.
Where is my UK pension taxed after the move?
Under the treaty, periodic pensions are in principle taxed in the country of residence, so the US. Lump sums from a UK pension scheme may be taxed only by the UK. For US citizens and green card holders the saving clause adds special points.
Can I keep my ISA?
Yes, but you can no longer pay in. The UK exemption only applies in the UK; settle the US treatment with the US side.
What if I return to the UK after three years?
Then the temporary non-residence rules usually apply: certain gains and distributions from your time in the US are taxed in the UK in the year you return.
Sources: HMRC: RDR3 Statutory Residence Test (SRT) notes; HMRC Residence and FIG regime manual: Temporary non-residence (RFIG21510, RFIG21560); GOV.UK: 2001 UK-USA Double Taxation Convention as amended by the 2002 protocol; GOV.UK: Tax on your UK income if you live abroad; IRS: U.S. tax residency, green card test; IRS: Substantial presence test; IRS: Introduction to residency under U.S. tax law; GOV.UK: Individual Savings Accounts, if you move abroad; GOV.UK: Capital Gains Tax on UK property or land if you're not a UK resident; HM Treasury: Budget 2026; GOV.UK: Inheritance Tax if you're a long-term UK resident; GOV.UK: Inheritance Tax Double Taxation Relief; HMRC International Manual: Company residence (INTM120040, INTM120085); HMRC: HS300 Non-residents and investment income (2026)
