UK Tax on US Social Security Benefits: Who Taxes It and How to Report It

UK tax on US Social Security applies to anyone who is UK resident: Article 17(3) of the US-UK tax treaty makes US Social Security paid to a UK resident taxable only in the UK. HMRC charges Income Tax on the full amount, reported on the SA106 Foreign pages, and the US does not tax it, even for US citizens. That single treaty sentence decides where the tax falls. The rest of this guide covers how HMRC works out the bill, where the benefit goes on the return, and the points where retirees most often go wrong.

This article is for UK residents who receive US Social Security retirement, survivor or disability benefits: American retirees who have settled in Britain, British nationals who spent part of their career in the US, and dual citizens. If you are thinking about the move itself, our guide to retiree tax across US and UK pensions covers the wider picture, including 401(k)s, IRAs and UK workplace pensions.

Is US Social Security taxable in the UK?

Yes. US Social Security is taxable in the UK when the person receiving it is UK resident for the tax year. Article 17(3) of the 2001 US-UK Income Tax Convention says payments made by one country under its social security legislation to a resident of the other country "shall be taxable only in that other State".

HMRC reads the article the same way. Its Double Taxation Relief Manual at DT19853 describes Article 17(3) as giving exclusive residence-country taxation of social security benefits. For a UK resident, that means US Social Security sits alongside UK income and is taxed at the normal UK rates.

The rule runs both ways. A US resident who draws the UK State Pension is taxed on it only in the US. Our article on the UK State Pension and US Social Security covers that mirror-image case and how the two systems count each other's contribution years.

Why the US does not tax a UK resident's Social Security, even for US citizens

The US taxes its citizens wherever they live. The treaty keeps that right through the saving clause in Article 1(4), which lets the US tax its citizens "as if this Convention had not come into effect". Most treaty benefits therefore do nothing for an American living in London.

Article 17(3) is one of the exceptions. Article 1(5)(a) lists "paragraphs 3 and 5 of Article 17" among the provisions the saving clause does not affect, and that exception applies to citizens as well as residents. Our explainer on the US-UK treaty saving clause goes through the full list.

IRS Publication 915 (for 2025 returns) puts this into practice in two places:

• US citizens who are residents of the United Kingdom are listed as exempt from US tax on their benefits, and the SSA does not withhold US tax from a US citizen's benefits.
• Nonresident aliens who are residents of the United Kingdom are listed as exempt under the treaty. Without a treaty, 85% of a nonresident alien's benefits is taxed at a flat 30%. Publication 915 says the SSA does not withhold from benefits that are exempt because the recipient lives in a listed treaty country.

The SSA still sends an annual statement: Form SSA-1099 to US citizens and Form SSA-1042S to nonresident aliens. Keep it. It is the US record of what was paid, and it shows any US tax that was withheld. If a UK-resident non-citizen's SSA-1042S shows tax withheld, take it up with the SSA and your adviser. It is a US refund matter, not something HMRC will credit.

How HMRC works out UK tax on US Social Security

HMRC charges UK tax on US Social Security on the full amount received in the UK tax year. Section 679 of the Income Tax (Earnings and Pensions) Act 2003 charges foreign social security income on "the full amount" arising in the tax year, and section 575 uses the same wording for foreign pensions. Whichever heading HMRC applies to a particular US benefit, the whole of it is taxable.

That full amount is added to your other income and taxed at the normal rates. For 2026/27 (6 April 2026 to 5 April 2027), GOV.UK lists these rates for England, Wales and Northern Ireland. Scotland sets its own bands.

2026/27 band (England, Wales, NI)	Taxable income	Rate
Personal Allowance	Up to £12,570	0%
Basic rate	£12,571 to £50,270	20%
Higher rate	£50,271 to £125,140	40%
Additional rate	Over £125,140	45%

The Personal Allowance falls by £1 for every £2 of adjusted net income above £100,000, so a large Social Security award combined with other income can cost the allowance as well.

Two practical points follow from the "full amount" rule:

• No 85% cap in the UK. The US rule that taxes at most 85% of benefits is a US rule. HMRC taxes 100% of what you receive.
• Convert each payment into pounds. The SA106 notes say to convert overseas income into pounds using the exchange rate at the time the income arose. Monthly benefits therefore need monthly conversions, not one figure at the year-end rate.

How do I report US Social Security on a UK tax return?

US Social Security is reported on the SA106 Foreign pages of a Self Assessment return, in the section headed "Overseas pensions, social security benefits and royalties". GOV.UK's guidance on who must send a return lists foreign income as one of the reasons you need one. The steps are:

1. Register for Self Assessment if you do not already file. The deadline is 5 October after the end of the first tax year in which you had the income. Our guide on whether you need to file Self Assessment in the UK covers the registration step.
2. Gather the payments for the UK tax year. The SSA-1099 and SSA-1042S cover the calendar year, but the UK tax year runs from 6 April to 5 April. Use your bank statements or the SSA's monthly benefit amounts to total the payments that fell between those dates.
3. Convert each payment into pounds at the exchange rate when it arose, as the SA106 notes require.
4. Complete columns A to F of the overseas pensions and social security section for the US payments, and carry the taxable total to box 9.
5. Make any FIG claim on the SA109 residence pages if you qualify, and enter the amount you are claiming relief on in box 9.1.
6. File and pay by 31 January after the end of the tax year, or let HMRC collect the tax through your PAYE code if you also have a UK pension and HMRC agrees to code it out.

Our walkthrough of the SA106 Foreign pages covers the other sections you may need, such as US dividends and interest, if you hold US investments as well.

Illustrative example: a retired US citizen living in Bath receives US Social Security of $2,000 a month and a UK workplace pension of £10,000 a year. For 2026/27, assume for illustration only that every Social Security payment converts at $1.30 to £1, giving £18,461.54 for the twelve payments in the UK tax year. Total income is £28,461.54. After the £12,570 Personal Allowance, £15,891.54 is taxed at the 20% basic rate, a UK bill of £3,178.31. Under Article 17(3), the US charges nothing on the Social Security. The workplace pension has its own US reporting, which our retiree guide covers. Real exchange rates change every month, so the actual sterling figure will differ.

The FIG regime: when a new arrival can pay no UK tax on US Social Security

The UK's foreign income and gains (FIG) regime replaced the remittance basis on 6 April 2025. Under the GOV.UK eligibility rules, a person in one of their first 4 tax years of UK residence, after at least 10 consecutive tax years of non-UK residence, can claim relief from UK tax on qualifying foreign income.

HMRC's Residence and FIG Regime Manual at RFIG45100 lists "foreign social security benefits" as qualifying foreign income, and foreign pension income too, apart from disqualified types. A qualifying American who retires to the UK can therefore choose to claim FIG relief on US Social Security for up to four years.

The claim has a cost. Anyone who claims FIG relief loses the Income Tax Personal Allowance and the Capital Gains Tax annual exempt amount for that year, and the relieved income still counts towards adjusted net income for some purposes. For a retiree whose only UK-taxable income is a modest pension, losing £12,570 of allowance can cost more than the relief saves. Run the numbers both ways before claiming. Our guide to the FIG regime explains how the claim works.

Who taxes US Social Security: a decision table

The answer depends on where you live and, for the US side, on very little else. This table sets out the common cases under the treaty and Publication 915.

Your situation	UK tax on US Social Security	US tax on US Social Security
US citizen, UK resident	Yes, on the full amount (Article 17(3))	No: exempt, saving clause does not apply (Article 1(5)(a), Publication 915)
British or other non-US national, UK resident	Yes, on the full amount	No: exempt as a UK treaty resident (Publication 915)
Qualifying new UK resident claiming FIG relief	No, for the years claimed, at the cost of the Personal Allowance	No: exempt under Article 17(3)
Anyone resident in the US	No: not UK resident, so UK tax does not reach this foreign income	Yes, under normal US rules

Residence in this table means residence under the treaty. Most people are resident in only one country. If you have homes in both and could be resident in both, the treaty's tie-breaker in Article 4 decides which country counts. The result can move the taxing right, so settle it before you file.

What people get wrong about UK tax on US Social Security

The same handful of errors comes up again and again on returns that cover US Social Security:

• Assuming the treaty makes it tax-free everywhere. Article 17(3) moves the tax to the UK. It does not remove it.
• Applying the US 85% rule on the UK return. HMRC taxes the full amount.
• Using the SSA-1099 total as the UK figure. The form covers a calendar year. The UK return needs the payments made between 6 April and 5 April, converted payment by payment.
• Reporting it as a UK pension. The SA106 notes say only pensions from foreign schemes registered in the UK go in the UK pensions section of the main return. US Social Security belongs on the Foreign pages.
• Claiming foreign tax credit relief. There is normally no US tax to credit, and the SA106 notes say foreign tax credit relief cannot be claimed on income you are claiming FIG relief on.
• Claiming FIG relief automatically. For many retirees the lost Personal Allowance outweighs the relief.
• Leaving it off the US return entirely without advice. The benefits are exempt from US tax, but you still file a US return if your other income requires one. Ask your adviser how to show the exemption.

Getting UK tax on US Social Security right

The rule is clear: a UK resident pays UK tax on US Social Security and the US steps back. The work is in the detail of conversions, tax years, the right SA106 boxes, the FIG choice and the US return that still needs filing. US/UK Cross Border Tax is US CPAs and UK tax advisers working as one team, with offices in London, Manchester, New York and San Francisco. We prepare both returns together so the benefit is reported once, in the right place.

If you are retiring to Britain or already drawing benefits here, see our advice on UK tax on US Social Security for retirees, our US-UK pensions service and our UK Self Assessment service, or contact us to talk through your position.