US–UK dual citizenship taxes: how dual citizens avoid double taxation

Being taxed twice on the same income is the fear that brings most people to us. In practice it is largely avoidable, but only if the two returns are prepared with each other in view.

Why it arises

The United States taxes its citizens and green card holders on worldwide income wherever they live. The UK taxes its residents on UK income and, for most residents, worldwide income too. A US citizen living in the UK is therefore inside both systems at once.

The three mechanisms

Foreign Tax Credit (Form 1116). UK income tax paid is credited against US tax on the same income, basket by basket. In a higher-tax country this is usually the main relief and often reduces US tax to nil. See the Foreign Tax Credit guide.

Foreign Earned Income Exclusion (Form 2555). Excludes up to US$130,000 (2025) of earned income from US tax. Simpler, but it produces no credits, does not cover investment income and has knock-on effects for the Child Tax Credit and IRA contributions. See the FEIE guide.

The US–UK treaty. Allocates taxing rights for pensions, dividends, employment income and more, but the saving clause means it reduces US tax for US citizens only in specific cases, chiefly pensions. See the treaty guide.

Dual citizens

A UK national who is also a US citizen files in the US every year, maintains FBAR and Form 8938 compliance and may owe US tax on UK income even after decades in the UK. Renouncing US citizenship ends that, but it has its own requirements: five years of tax compliance, Form 8854, and a potential exit tax under section 877A for covered expatriates. It is a personal decision; we can set out the tax consequences in writing.

Green card holders are in the same position until the card is formally abandoned, and long-term residents (8 of the last 15 years) face the same exit-tax rules.

How the UK decides whether to tax you

Statutory Residence Test

UK residence for a tax year is decided by the Statutory Residence Test: automatic overseas tests, automatic UK tests (including 183 days in the UK) and, if neither applies, a sufficient-ties test combining day counts with ties such as family, accommodation and work. Split-year treatment can apply in the year you arrive or leave.

The end of the remittance basis

From 6 April 2025 the remittance basis for non-domiciled residents was abolished. New arrivals who were non-UK resident for the previous ten tax years can claim relief on foreign income and gains for their first four years of UK residence under the FIG regime; after that they are taxed on worldwide income like any other resident. The claim is made on the Self Assessment return and interacts with the US return, so both should be modelled before claiming.

Common situations

• UK salary. Taxed in both countries; UK PAYE is credited on Form 1116 and usually eliminates US tax on it.
• UK dividends and interest. Credited within the passive basket; residual US tax can arise where UK rates are lower than US rates, and ISA income has no UK tax to credit at all.
• Selling a UK home. UK Private Residence Relief and the US Section 121 exclusion are different; the US also taxes the currency element of the gain. UK residential disposals are reported to HMRC within 60 days.
• UK pensions. Governed mainly by the treaty's pension article, with lump sums needing specific analysis.
• Self-employment. Income tax is credited; social security is decided by the Totalization Agreement, with a certificate of coverage removing US self-employment tax for UK residents.

What good coordination looks like

The UK return is prepared first where UK tax drives the US credit, UK-year figures are apportioned to the US calendar year with a documented method, and treaty positions are stated consistently on both returns. One file, both returns, one set of figures.