Do US Expats in the UK Pay Tax Twice?
No. Not in most cases. You’ll usually need to file in both countries, but that doesn’t mean you’ll be taxed twice on the same income. The system is set up, somewhat intentionally, to prevent that. Between credits, exclusions, and treaty rules, most Americans in the UK end up paying tax primarily in one place.
Still, it doesn’t always feel that simple when you’re looking at two tax returns.
Why Double Taxation Happens in the First Place
It comes down to how each country defines who it taxes.
The Internal Revenue Service taxes based on citizenship. So even if you’ve lived in the UK for years, you’re still on the hook to report your worldwide income.
The UK, through HM Revenue & Customs, taxes based on residency. If you’re considered a UK tax resident, the UK also expects to tax your worldwide income.
Same person. Same income. Two systems looking at it from different angles.
The Foreign Tax Credit: The Most Common Solution
If there’s one tool most US expats in the UK end up relying on, it’s the Foreign Tax Credit.
In simple terms, it allows you to take the tax you’ve already paid in the UK and apply it against your US tax liability. So if you’ve paid more tax in the UK than you would owe in the US, your US tax can drop to zero.
You claim it using Form 1116, and while the mechanics can get a bit detailed, the outcome is usually straightforward. Because UK tax rates are often higher, the credit tends to fully offset US tax for many expats.
It’s not perfect. Timing differences can complicate things. But as a general rule, this is what prevents most people from actually paying twice.
The Foreign Earned Income Exclusion (FEIE)
Then there’s the Foreign Earned Income Exclusion.
For 2025, it lets you exclude around $130,000 of earned income from US tax, assuming you meet the eligibility tests. On paper, that sounds like the obvious solution.
In practice, it depends.
The exclusion only applies to earned income. Salary, freelance work, that sort of thing. It doesn’t cover investment income. And in a country like the UK, where taxes are already relatively high, using the exclusion instead of the credit can sometimes limit your ability to offset taxes fully.
So while FEIE has its place, it’s not always the default choice people assume it is.
The US-UK Tax Treaty: What It Actually Does
The US-UK Tax Treaty sits quietly in the background of all this.
It helps determine which country gets the primary right to tax certain types of income. Pensions, for example, or certain types of investment income. It also provides mechanisms to reduce overlap.
However, there’s a catch. The US includes what’s called a “saving clause,” which means it can still tax its own citizens as if the treaty didn’t exist in many situations.
So the treaty helps. It just doesn’t override everything.
Which Strategy Works Best for US Expats in the UK?
If you’re earning a typical salary in the UK, the Foreign Tax Credit often comes out ahead.
That’s largely because UK taxes are already higher, so you’re effectively using those payments to cancel out your US liability. FEIE can still work in certain situations, especially if your income is lower or structured differently, but it’s rarely a one-size-fits-all decision.
Some people even use a mix of both approaches, depending on their income types. That’s where things start to feel less obvious and more… situational.
Situations Where Double Taxation Can Still Happen
Even with all these tools, there are moments where things don’t line up perfectly.
The tax year mismatch is one. The UK runs April to April, while the US sticks to the calendar year. That can create timing gaps when claiming credits.
Investment income is another. ISAs, for instance, are tax-free in the UK but not in the US. And UK-based funds can trigger PFIC rules, which come with their own complications.
So while double taxation is usually avoided, it’s not entirely impossible if things aren’t handled carefully.
What If You’re a US-UK Dual Citizen?
You might think having both passports changes the equation. It doesn’t, at least not in terms of tax rules.
You still file in both countries. You still rely on the same credits, exclusions, and treaty provisions.
What US-UK dual citizenship does offer, though, is flexibility. It gives you more control over where you live, how long you stay, and how you structure your life over time. That can open up planning opportunities, even if the core tax framework stays the same.
How to Avoid Double Taxation (Step-by-Step)
If you’re trying to keep things clean, it helps to follow a clear process:
- Confirm your UK tax residency status
- Report your worldwide income in both countries
- Apply the Foreign Tax Credit or FEIE correctly
- Use treaty provisions where they’re relevant
- Pay attention to timing differences between tax years
None of this is particularly mysterious on its own. It’s the combination that tends to trip people up.
Need Help Avoiding Double Taxation?
Most of the time, the issue isn’t that the rules don’t exist. It’s figuring out which ones apply to you, and when.
Between credits, exclusions, treaty rules, and reporting requirements, it’s easy to miss something small that ends up mattering later. Expat Tax Online works with Americans in the UK dealing with exactly this kind of overlap, helping you line things up properly from the start rather than fixing it after the fact.
