Can you claim both US Social Security and the UK State Pension?

Yes, you can claim both. If you've worked and paid into the system in both the US and UK, you're generally entitled to a retirement benefit from each country independently. They don't cancel each other out. There is a catch, though - a US rule called the Windfall Elimination Provision that dents your Social Security if you're also drawing a UK State Pension. It doesn't wipe it out, but it can take a meaningful bite. Worth understanding before you retire.

Two independent systems

The two pensions are administered completely separately. US Social Security is based on what you earned in SS-covered employment in America. The UK State Pension is based on your National Insurance record in the UK. Neither system knows or cares what you built up in the other - they run in parallel and pay in their own currencies.

US Social Security requires 40 "credits" of work in a Social Security-covered job - roughly ten years of employment - to qualify for a retirement benefit. Your monthly payment is then calculated from your 35 highest-earning years in the US. If you spent years working in the UK instead, those years don't appear in the US calculation at all. They count as zeros, which pulls your average down and reduces your benefit.

The UK New State Pension (introduced in April 2016) requires at least ten qualifying years of National Insurance (NI) contributions to get anything at all, and 35 years to get the full amount - around £230 a week as of 2025, rising each April under the triple lock. Each year you worked and paid NI in the UK counts toward that total. You can also buy additional years voluntarily from abroad if you have gaps.

Your UK NI years don't count toward your US Social Security record, and vice versa. With one exception.

The US-UK Totalization Agreement

The US and UK have had a Totalization Agreement running since 1984. Its main job is stopping workers from paying into both systems at once - while you're working abroad, you generally pay into just one system depending on where you're based and for how long.

But it also has a useful safety net. If you don't have enough credits in one country to qualify for a benefit on your own, contributions from the other can be counted purely to get you over the threshold. So if you have 8 years of US Social Security credits and 15 years of UK NI, the SSA can use those UK years to confirm you've hit the qualifying minimum. You'd still only get a US benefit calculated on your actual US earnings - the UK years don't inflate the payment, they just get you through the door.

It works the other way too. Short of ten UK qualifying years? US credits can get you to the minimum, and you'd receive a pro-rated UK State Pension based on whatever NI years you actually have.

The Windfall Elimination Provision - the part most people miss

The Windfall Elimination Provision (WEP) is a US rule that reduces Social Security retirement benefits for anyone who also receives a pension from work that wasn't covered by Social Security - and that includes foreign state pensions like the UK State Pension.

The reasoning: Social Security's formula is designed to replace a higher proportion of income for lower earners. Someone who spent years working in the UK looks like a low US earner on paper, because those UK years produced no US earnings record. Without WEP, they'd get the low-earner weighting even though their lifetime earnings weren't low at all. WEP corrects for that by applying a less generous formula to the first portion of average monthly earnings.

In dollar terms, WEP can cut your monthly Social Security by up to around $600 - the exact cap shifts each year. But the reduction can't exceed half the value of the foreign pension you're receiving, so if your UK State Pension is modest, your exposure is limited too.

It doesn't cancel your Social Security. It reduces it - sometimes significantly, sometimes only a little, depending on your earnings history. And if you've got 30 or more years of substantial earnings in SS-covered work, WEP doesn't apply at all. Between 21 and 29 years, the reduction phases down gradually.

Side-by-side comparison

Tax: where it gets complicated

Both countries will want a slice. The US-UK Double Taxation Convention is there to stop the same income being taxed twice, but how it works depends on where you actually live in retirement.

If you're a US resident, your UK State Pension is generally taxable in the US, not the UK. If you're a UK resident, your Social Security is generally taxable in the UK, not the US. Retire somewhere else entirely and different treaty rules apply.

This gets complicated quickly - especially if you hold US citizenship, which means the US taxes your worldwide income regardless of where you live. A tax adviser who knows both systems isn't a luxury here. The cost of getting the treaty position wrong across a 20-year retirement adds up fast.

What it looks like in practice

Take someone who worked 18 years in the UK and 17 years in the US, retiring at 67.

• UK State Pension: 18 qualifying years out of 35 = 51% of the full rate, so around £117 a week or £6,100 a year.
• US Social Security: calculated on 17 years of US earnings, then reduced by WEP. Depending on what those earnings looked like, WEP might take $300-$400 a month off the benefit, leaving somewhere in the range of $1,200-$1,500 a month.

That's two income streams arriving every month in retirement, in two currencies. Neither depends on what investment markets are doing. As a foundation to build on, it's not nothing.

Voluntary NI contributions - don't overlook this

If your UK qualifying years are short of 35, you can buy more from abroad. Class 2 and Class 3 voluntary contributions cost a few hundred pounds a year, and each extra year adds roughly £6-7 to your weekly State Pension for life. If you're five or ten years short, the maths often works out very well - a few thousand pounds now buying hundreds of pounds a year permanently.

Check your NI record and get a forecast at gov.uk/check-state-pension, then use the HMRC voluntary NI payment service to fill the gaps. Don't leave it too long - this option closes once you start drawing the pension.

Putting both pensions in one plan

This is exactly why I built RetireFlexi. When I was trying to figure out my own retirement, I couldn't find anything that let me look at my US and UK entitlements alongside each other in a single picture. The calculator does that:

1. Add your US Social Security as a state pension under United States - use the projected benefit from your SSA statement, and nudge it down to account for WEP if it applies to you
2. Add your UK State Pension as a second state pension under United Kingdom - use your forecast from gov.uk
3. Set each to start at the right age, or later if you're planning to defer
4. The year-by-year table shows how both income streams combine with whatever you're drawing from investments

The Dashboard pulls it all together - your guaranteed income floor from both state pensions, your withdrawal rate from the investment pot, and a Monte Carlo probability for how likely your plan is to hold up across different market scenarios. It's the view I wanted and couldn't find anywhere else.

If you're also weighing up where to retire once you know how your income splits across two countries, the guide to the best expat retirement countries in 2026 covers visa costs, healthcare, and the tax traps that make a cheap country expensive. Portugal is one of the most popular choices — the 2026 Portugal retirement guide has the specific tax maths for UK and US pension income.