US UK Tax for Retirees: A Month-by-Month Filing Calendar

US UK tax for retirees: an introduction

US UK tax for retirees comes down to two returns on two different years, plus a treaty that decides which country taxes each pension. For a US citizen living in Britain, US Social Security is generally taxed only in the UK. Meanwhile, the US can still tax a UK State Pension and IRA withdrawals, with credit for UK tax. The hard part is not the rules but the timing.

This article supports our guide to US and UK tax returns prepared together. It is for Americans who are already up to date with their filings. If you are behind, read about catching up first, because this calendar assumes a clean starting point.

Why US UK tax for retirees needs a calendar

The UK tax year runs from 6 April to 5 April. The US tax year is the calendar year. As a result, each pension payment lands in one UK year and one US year, and the two rarely line up. A calendar that merges both years is the simplest way to stay ahead.

What we assume

We assume you are a US citizen, UK resident, retired, and drawing some mix of US Social Security, an IRA or 401(k) and a UK State Pension. We also assume no employment income. Anyone still working, or holding UK funds, will have extra steps.

Which country taxes each retirement income?

US Social Security paid to a UK resident is taxable only in the UK, even for a US citizen. IRA and 401(k) withdrawals are taxed by the UK, with the US also taxing its citizens and giving credit. The UK State Pension is taxed in the UK, and in our reading the US also taxes it for a citizen.

US Social Security

Article 17(3) of the US-UK income tax treaty gives social security benefits to the residence country. The saving clause would normally let the US tax its citizens anyway. However, Article 17(3) is one of the listed exceptions. The Treasury Technical Explanation confirms that a US citizen resident in the UK is not subject to US tax on US social security benefits.

IRA and 401(k) withdrawals

Article 17(1)(a) gives pensions to the residence country, so the UK taxes your IRA withdrawals. That paragraph is not an exception to the saving clause, so the US still taxes a citizen. Article 24(6) then sorts out the credit, re-sourcing income where needed. In practice, the UK usually taxes first and the US gives a foreign tax credit on Form 1116.

Roth accounts and the UK State Pension

Article 17(1)(b) tells the UK to exempt amounts the US would exempt for its own residents. That is why qualifying Roth IRA withdrawals are usually free of UK tax as well, a useful point in US UK tax for retirees. The UK State Pension is different. It is paid by the UK to a UK resident, so Article 17(3) does not reach it. In our reading the US taxes it like any other citizen's pension, with credit for UK tax. Some preparers take other views, so treat it as a point to confirm.

How is UK tax on the State Pension collected?

The State Pension is paid without tax taken off. HMRC collects the tax through the tax code on another pension, or by sending a Simple Assessment bill. If you file Self Assessment, it goes on your return instead.

The tax code route

GOV.UK's page on how tax on pensions is paid explains that the State Pension is not taxed before you receive it. Where you have a UK private or workplace pension too, HMRC adjusts that pension's tax code. That way, the State Pension tax comes off the other payment.

Simple Assessment

If the State Pension is your only UK-taxed income and it exceeds your Personal Allowance, HMRC may send a Simple Assessment bill. Payment dates depend on when the letter is issued. However, most American retirees have US income to report as well. They file Self Assessment, and the State Pension simply goes on that return.

Rates and the frozen allowance

For 2026 to 2027, the full new State Pension is £241.30 a week. The Personal Allowance is £12,570, and the government has frozen it until 5 April 2031. Budget 2026 also announced a Pension Tax Allowance from April 2027, aimed at small State Pension tax bills. It is not yet law.

What happens in each month of the year?

Most deadlines fall in January, April, June, July, October and December. The calendar below runs from January, because that is when the first tax papers arrive. Each month names what to do for both countries.

January to March

January is the busiest month. Your UK online return and any balance are due on 31 January, along with the first payment on account. The fourth US estimated tax instalment is due in mid-January. Your US pension forms for the past year also start arriving early in the year. February and March are quieter, so use them to gather US figures.

April to June

On 5 April the UK tax year ends, and the State Pension rises from 6 April. The US return and payment are due on 15 April. People living abroad get an automatic two-month extension to 15 June to file. However, interest runs on unpaid tax from 15 April. The first two US estimated payments fall on 15 April and 15 June.

July to September

The second UK payment on account is due on 31 July. The third US estimated payment is due on 15 September. Summer is a good time to file the US return if you have not yet done so, because the UK return for the year just ended can now be drafted too.

October to December

The FBAR is due on 15 April with an automatic extension to 15 October. A US return extended on Form 4868 is also due then. UK paper returns are due on 31 October, as GOV.UK's Self Assessment deadlines page shows. Finally, take your required minimum distribution by 31 December, and note every account's year-end value.

How do required minimum distributions fit the calendar?

Required minimum distributions start at age 73. The first is due by 1 April of the following year, and each later one by 31 December. The UK has no equivalent rule, but it taxes the payment when it arrives.

The US rule

A required minimum distribution, or RMD, is the minimum you must take each year from an IRA or similar plan. The IRS RMD page sets the starting age at 73. Roth IRAs have no RMDs for the original owner.

The timing trap

Taking the first RMD in the following January to March can mean two RMDs in one US year. For the UK, both payments might also fall in one tax year. Consequently, a single delay can push you into a higher band in both countries. Plan the date with both years in mind.

Withholding and credits

US plan administrators may withhold US tax from IRA payments unless told otherwise. For a UK resident, the treaty usually means the UK tax is primary. Therefore, check withholding instructions each year, so you are not waiting for a large US refund while also paying UK tax.

What does a retiree's year look like in practice?

A typical retiree files one UK return and one US return, plus an FBAR, each year. The example shows where each income goes. It deliberately avoids tax figures, because those depend on exchange rates and other income.

A worked example

Consider a typical case. Carol, a fictional US citizen aged 75, lives in Gloucestershire. She receives US Social Security, takes an RMD from her traditional IRA each December, and draws a small UK State Pension from years of work in Britain. She also holds a UK bank account and a US brokerage account.

On her UK return, Carol reports the Social Security, the IRA withdrawal and the State Pension. On her US return, she reports the IRA withdrawal and the State Pension, and claims credit for UK tax. She leaves out the Social Security under Article 17(3), and attaches Form 8833 where required. Her UK account goes on the FBAR if her foreign accounts pass $10,000 in total.

Carol's calendar

In January, Carol files her UK return and pays her balance. In June, she files her US return using the abroad extension, having paid any US tax by 15 April. In October, the FBAR deadline passes without stress because she filed it in June. In December, she takes her RMD and notes her balances. That is US UK tax for retirees reduced to four dates.

How do exchange rates affect US UK tax for retirees?

Every payment must be converted, into pounds for HMRC and into dollars for the IRS. The rate you use changes the income on each return and the credit available. Choosing a method and keeping to it matters more than the method itself.

Two currencies, two years

US Social Security and IRA payments arrive in dollars, but HMRC needs them in pounds. The UK State Pension arrives in pounds, but the IRS needs it in dollars. IRS Publication 54 requires every amount on a US return to be in dollars. Consequently, US UK tax for retirees always involves two sets of conversions for the same money.

Matching the credit to the income

The foreign tax credit works best when the UK tax is converted on a basis that matches the income. If the pension and the tax are converted at very different rates, the credit can fall short. Therefore, we keep a simple schedule of each payment, its date and the rate used. That schedule supports both returns.

Bank transfers and charges

Many retirees have US pensions paid into a US account and then move money to Britain. The transfer itself is not income, but the bank's rate and fees can confuse the records. Keep transfer confirmations apart from the pension statements, so the income figures stay clean.

Which mistakes do retirees make most often?

The commonest are reporting Social Security on the US return, missing the FBAR, and paying US tax on an IRA without claiming the UK credit. Each is easy to avoid with a calendar built for US UK tax for retirees.

Taxing Social Security twice

Many US software packages include Social Security automatically. For a UK resident, the treaty usually takes it out. If you prepare your own US return, check this line first. Some retirees have paid US tax on it for years without realising.

Forgetting the FBAR

A retiree's UK current account alone can pass $10,000. The FinCEN FBAR page explains the aggregate test. Our article on the FBAR deadline covers dates and extensions.

Missing the UK registration date

For US UK tax for retirees, the first UK return is often the one that slips. If you need Self Assessment for the first time, register by 5 October after the tax year ends. Our article on Self Assessment for Americans in the UK explains the process.

How US UK Tax Experts can help

US UK Tax Experts prepares the US and UK returns from one file, so that the two agree. For US UK tax for retirees, that means placing each pension on the right return, applying the treaty and claiming credit in the right year. See our pensions service and our US federal returns service.

Conclusion

Retirement income crosses the Atlantic easily, but the tax years do not. The treaty gives US Social Security to the UK, and lets the US tax most other pensions with credit. Build your year around January, April, June, October and December, and US UK tax for retirees becomes a routine rather than a scramble.

Contact us

If you are retired in Britain and file in both countries, email hello@usuktaxexperts.com or use our contact page. Tell us each pension you receive and where it is paid from. We reply within one working day.