UK pension contributions and US tax meet in Article 18(5) of the US–UK treaty. A US citizen working in Britain can deduct personal contributions to a UK scheme and exclude employer contributions on Form 1040 — but only where the contributions get UK tax relief, and only up to what a comparable US plan would allow.
Without that paragraph, an American in a British workplace pension would pay US tax on money the UK has deliberately sheltered. With it, most employees are protected. The exceptions sit at the edges: very high contributions, personal pensions unconnected to the job, and anyone working outside the UK.
What Article 18(5) actually says
Paragraph 5 of Article 18 is written specifically for US citizens resident in the United Kingdom, which is why it survives the treaty's saving clause when most treaty benefits do not. It applies where all of the following hold:
- You are a US citizen resident in the UK.
- You are a member of a UK pension scheme.
- You are employed in the UK and the scheme relates to that employment.
- The contributions qualify for UK tax relief.
Where they do, employer contributions are excluded from your US income and your own contributions are deductible. The limit is the key sentence: the relief cannot exceed what the United States would give its own residents for a generally corresponding US pension scheme. The treaty text is in the IRS's United Kingdom tax treaty documents.
How UK pension contributions are treated, type by type
| Contribution | UK treatment | US treatment under Article 18(5) |
|---|---|---|
| Employer contribution to a workplace scheme | Tax relief, no benefit in kind | Excluded from income, within the cap |
| Employee contribution, net pay arrangement | Deducted from gross pay before tax | Deductible, within the cap |
| Salary sacrifice | Treated as an employer contribution | Generally excludable as an employer contribution, within the cap |
| Personal pension or SIPP, relief at source | Basic rate added by HMRC, higher rate claimed on the return | Less settled — depends on the link to your UK employment |
| Contributions above the cap | Relieved up to the UK annual allowance | Taxable on the Form 1040 |
The workplace scheme is the safe case. A SIPP funded independently of your employer is where practitioners disagree, so treat any deduction for it as a position to be disclosed, not an entitlement.
The cap: what a "generally corresponding" US plan allows
The comparison most practitioners draw is with a US 401(k). For 2026 the IRS sets the elective deferral limit at $24,500, as announced in its 2026 contribution limits, and total annual additions from employer and employee combined are capped separately under section 415(c).
The UK is far more generous at the top. The annual allowance for 2026-27 is £60,000, tapered for very high earners, with carry-forward of unused allowance from the previous three years. Anything a UK employee contributes beyond what the US cap would allow gets full UK relief and no US relief at all.
An illustrative case, using an exchange rate of $1.30 to £1 for the arithmetic only:
- An employee contributes £12,000 through net pay, about $15,600 — inside the $24,500 deferral limit, so deductible.
- The employer contributes £18,000, about $23,400 — excludable, and the combined $39,000 sits well inside the annual additions limit.
- Had the employee also used carry-forward to add £40,000 in the same year, most of that extra would be taxable on the US return despite being fully relieved in Britain.
How the position is claimed
The treaty benefit is claimed on the return rather than granted automatically. In practice wages are reported net of the qualifying contributions, and the treaty position is disclosed on Form 8833. Disclosure costs nothing; an undisclosed treaty position that turns out to need disclosure carries a $1,000 penalty for an individual.
The claim also interacts with your foreign tax credit. Excluding contributions lowers your US taxable income, but the UK tax relief on the same contributions lowers the UK tax available as a credit. Our pillar on foreign tax credits explains why that trade-off usually still favours claiming the relief, and the treaty background is in the US–UK tax treaty.
Where Article 18(5) does not help
- State tax. The treaty binds the federal government only. A state that still treats you as resident can tax the contributions the treaty excludes.
- Contributions above the US cap. Fully relieved in Britain, taxable in America.
- Working outside the UK. The paragraph requires UK employment; an American working for a UK scheme from Dubai or New York is outside it.
- Reporting. Relief on contributions does not remove the pension from your FBAR or Form 8938. See transferring a UK pension abroad for how the fund is treated later.
HMRC explains the UK side of relief in its guidance on tax on your private pension contributions.
Tranzesta prepares both returns together, so contribution levels are set against the US cap before the tax year ends rather than discovered afterwards. Book a consultation if you are contributing heavily or using carry-forward.
Frequently Asked Questions
Can I deduct UK pension contributions on my US tax return?
Usually yes, if you are a US citizen resident and employed in the UK. Article 18(5) of the US–UK treaty lets you deduct your own contributions and exclude your employer's, provided the contributions qualify for UK tax relief. The relief is capped at what a generally corresponding US plan would allow, commonly measured against the 401(k) limits — $24,500 of elective deferrals for 2026.
Are employer pension contributions taxable in the US?
Not for a US citizen employed in the UK whose contributions meet Article 18(5). Employer contributions to a UK workplace scheme are excluded from US income, within the cap set by a comparable US plan. Contributions above that cap, or contributions made while working outside the UK, fall outside the treaty and can be taxable in the year they are made.
Does UK salary sacrifice work for US tax?
Generally yes, within limits. A properly constituted salary sacrifice is treated as an employer contribution, which Article 18(5) allows a US citizen employed in the UK to exclude from US income. The risk is scale: sacrificing more than a comparable US plan would permit leaves the excess taxable in the US while fully relieved in the UK.
Can I deduct SIPP contributions on Form 1040?
It is less certain than for a workplace scheme. Article 18(5) requires the scheme to relate to your UK employment, and a SIPP funded independently of your employer may not meet that condition. Some practitioners take the deduction and disclose it on Form 8833; others treat SIPP contributions as non-deductible. Decide deliberately and apply the position consistently.
What happens to the deduction if I move back to the US?
Article 18(5) stops applying once you are no longer resident and employed in the UK. Other paragraphs of Article 18 can give continuing relief for contributions to a UK scheme you joined before moving, subject to conditions, but it should not be assumed. Review contribution levels before the move rather than after it.
Is there an equivalent if I work in the UAE?
No. There is no income tax treaty between the United States and the UAE, so there is no Article 18(5) equivalent. Contributions to a foreign plan are generally not deductible for US purposes, and employer contributions to a non-US plan can be taxable when they vest under section 402(b) of the Internal Revenue Code.
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