US·UK Accountants

Comparison

US Tax Return vs UK Tax Return

A US tax return and a UK tax return follow different principles. The US taxes citizens on worldwide income wherever they live (citizenship-based), while the UK taxes on the basis of residence. Americans in the UK often file both, using the foreign tax credit and the US–UK treaty to avoid being taxed twice on the same income.

SH

By Sam H., Founder & Lead Advisor

ACCA · ACA · Reviewed by Katie M. · 2025-01-15

The short answer

Two systems, two logics

The defining difference is what triggers the filing. The US return follows the person — a US citizen files wherever they live. The UK return follows residence, and sometimes domicile. For an American in the UK, both can apply at once.

Basis of taxation
Citizenship
Filed by non-residents (citizens abroad)
Reports worldwide income
Tax authority
IRS
Common for Americans in the UK

US Tax Return

Basis of taxation
Residence
Filed by non-residents (citizens abroad)
Reports worldwide income
Depends on residence/domicile
Tax authority
HMRC
Common for Americans in the UK

UK Tax Return

Basis of taxation
Filed by non-residents (citizens abroad)
Reports worldwide income
Tax authority
Common for Americans in the UK

Why filing both does not mean paying twice

Filing in two systems sounds like double taxation, but the mechanisms exist precisely to prevent that. The foreign tax credit lets UK tax offset US tax on the same income, the foreign earned income exclusion can remove qualifying earned income from US tax, and the US–UK tax treaty allocates taxing rights for particular income types.

The returns still have to be filed; the relief happens inside them. Coordinating the two is where most of the value — and most of the risk — sits.

This helps if you

  • Are a US citizen or green-card holder living in the UK
  • Are new to filing in two countries
  • Want to understand why both returns are needed
  • Are worried about being taxed twice

At a glance

US basis
Citizenship — worldwide income
UK basis
Residence (and sometimes domicile)
Authorities
IRS and HMRC
Double-tax relief
Foreign tax credit, FEIE, treaty

Frequently asked questions

Frequently, yes. The US taxes its citizens on worldwide income regardless of where they live, while the UK taxes based on residence. Many Americans in the UK therefore have obligations in both systems.

The US uses citizenship-based taxation: US citizens and green-card holders file US returns wherever they live. The UK uses residence-based taxation, focused on where you are resident and, in some cases, your domicile.

No. The two systems are independent. Filing in the UK does not discharge a US filing obligation, though mechanisms such as the foreign tax credit and the treaty help prevent the same income being taxed twice.

Through relief mechanisms rather than exemption from filing — chiefly the foreign tax credit, the foreign earned income exclusion, and provisions of the US–UK tax treaty.

Filing on both sides of the Atlantic?

We coordinate your US and UK filings so they work together and you never pay twice.