An American in the UK who finds a mistake on a US return already filed corrects it on Form 1040-X (opens the official IRS page in a new tab). The form can be filed electronically with tax software for recent years, or on paper to the IRS address for people living abroad. Each year needs its own form, and a refund claim generally has to be made within three years from filing or two years from payment, whichever is later, with a longer period for changes to the foreign tax credit.
This post is for US citizens and green card holders in Britain correcting an ordinary error: UK income left off, a foreign tax credit worked out wrongly, a credit not claimed, or the exclusion used where the credit would have done better. It goes deeper than the amendment points in our guide to US and UK tax returns for Americans in the UK. It covers when to amend, how to file from abroad, the time limits, what happens when UK tax changes after filing, switching between the exclusion and the credit, and the state and FBAR follow-on steps.
When an American in the UK should amend a US return
Amend when something on the filed return was wrong and it changes your filing status, income, deductions, credits, dependents or tax. Missed UK interest, a dividend left off, or a foreign tax credit worked on the wrong figures all qualify. You do not amend to fix an arithmetic slip the IRS has already corrected, or because a schedule it later asks for was missing.
The IRS page on filing an amended return draws that line. If the IRS writes to say it corrected an error, or accepts the return and asks for a missing form, the answer is to respond to the letter, not to file Form 1040-X. Our IRS representation work handles those replies. Everything else that changes the numbers on the return goes on an amended return for the year concerned.
For Americans in Britain the common triggers are cross-border ones. UK savings interest is easy to miss because the UK taxes little of it, yet it is fully reportable in the US. A foreign tax credit (opens the official IRS page in a new tab) may have used UK tax for the wrong year or the wrong category. A family may have claimed the exclusion and lost the refundable part of the child tax credit, as our post on the child tax credit for American families in Britain explains.
- UK bank interest, dividends or fund income left off the return
- UK tax credited in the wrong year or the wrong income category on Form 1116
- A credit not claimed, such as the child tax credit
- The exclusion claimed where the foreign tax credit gives a better result
- A filing status that should have been different
How to file Form 1040-X from the UK
Tax software can file Form 1040-X electronically to amend a Form 1040 or 1040-NR, which is usually faster and works from anywhere. Returns for tax year 2021 or earlier must go on paper. Paper forms from a UK address go to the Austin, Texas address that the Form 1040-X instructions list for filers in a foreign country.
That same address applies to anyone who uses an APO or FPO address, files Form 2555, or is a dual-status alien, wherever they live. It is not the dedicated Streamlined address, which is reserved for packages filed under those procedures. The IRS also says paper filing is needed where the original return was filed on paper earlier in the current year for an earlier tax year.
Each year is a separate Form 1040-X. The form shows the figures as originally reported, the net change and the corrected figures, and Part II asks for a plain explanation of why you are amending. The instructions say every form and schedule affected by the change must be attached, or the return may be sent back. For a credit change that means a revised Form 1116; for an exclusion change, the Form 2555. We prepare amendments as part of our individual US tax returns work.
- One Form 1040-X for each tax year being corrected
- Electronic filing through software for years after 2021
- Paper to the Austin address for filers in a foreign country
- A clear Part II explanation of each change
- Every revised form and schedule attached, such as Form 1116 or Form 2555
How long you have to claim a US refund
The general rule is three years from filing or two years from payment, whichever is later. A return filed before the due date counts as filed on 15 April. The Form 1040-X instructions give a longer period where the refund comes from a change to the foreign tax credit, but only for the part of the claim the credit change produces.
That longer period runs from the original due date, ignoring extensions, of the year in which the UK tax was paid or accrued. Publication 514 (opens the official IRS page in a new tab) describes it in the same terms: where you paid or accrued more foreign tax than you claimed a credit for, you have an extended period to claim the refund. It matters for Americans in Britain because UK tax often turns up late, for example when a Self Assessment return is corrected after the US return has been filed.
The longer window does not extend to unrelated changes in the same year. A missed dependant or a different filing status stays under the ordinary rule. Where an amendment increases the tax rather than reducing it, the instructions say interest runs from the original due date of the return, and the IRS advises paying any extra tax by 15 April where possible to limit penalties and interest.
What happens when your UK tax changes after you file
A later change in the UK tax you credited is a foreign tax redetermination, under section 905(c) of the Internal Revenue Code. If it changes your US tax for an earlier year, you generally file Form 1040-X for that year with a revised Form 1116 and a statement giving the IRS enough to recompute the liability.
The instructions for Form 1116 add a step for the year of the change. Schedule C of Form 1116 is attached to the current-year return for each category of income affected. Where the redetermination does not change the US tax for any year, no amended return is needed and the Schedule C alone is enough.
The most common example is HMRC repaying tax after an amended Self Assessment return or a late relief claim. Less UK tax means less US credit, so the US tax for that year can rise. Publication 514 says a reduction of this kind must be notified to the IRS, and that a failure to do so without reasonable cause attracts a penalty that grows each month until a cap. An increase in UK tax works the other way and can support a refund claim under the longer foreign tax credit period.
Switching from the exclusion to the foreign tax credit
The exclusion can be claimed on a return amending a timely filed return, and it can be given up on one. For most Americans in Britain, where UK tax is generally higher than US tax, the foreign tax credit gives the better result. Revoking the exclusion stops it being chosen again for five tax years without IRS approval.
The Form 2555 (opens the official IRS page in a new tab) instructions say the election, once made, stays in effect for that year and every later year until it is revoked, and that revocation is by a statement attached to the return for the first year you no longer want it. Our post on revoking the foreign earned income exclusion covers the statement and the bar, and Publication 54 (opens the official IRS page in a new tab) sets out when the IRS may consent to an earlier return.
Take a US citizen employed in Leeds who claimed the exclusion on her last US return and later learns that her UK tax exceeds the US tax on her salary. She files Form 1040-X for that year, removes Form 2555, attaches a revocation statement and a Form 1116, and claims the credit instead. Any unused UK tax in that category can then be carried back one year and forward ten years. Our post on choosing a foreign tax credit or exclusion in the UK compares the two.
What else to correct: state returns and the FBAR
Form 1040-X corrects the federal income tax return and nothing else. A state return built on the same figures may need its own amendment. A missed or wrong FBAR is not fixed on Form 1040-X at all: it is filed or amended with FinCEN, which is a separate agency with its own system.
The IRS says a change to the federal return may affect your state tax, and that the state return should not be attached to Form 1040-X. Former residents of some states remain within that state's reach after a move to London, so a federal amendment can mean a state one. Our multi-state tax filing team and our page on US state tax returns cover how states treat leavers.
The FBAR (opens the official FinCEN page in a new tab) is filed electronically with FinCEN and never with a tax return. A corrected report is a new FBAR marked as amended, completed in full, as our post on correcting a mistake on an FBAR you already filed describes. Ordinary amendments for one or two years are different from catching up after years of non-wilful non-compliance, where the Streamlined procedures may fit better. Our guide for Americans in the UK sets out the full annual filing cycle.
- Federal income tax: Form 1040-X for each year
- State income tax: the state's own amended return, filed separately
- FBAR: a new report marked as amended, filed with FinCEN
- Several years of missed filings: consider the Streamlined procedures
General information, not advice. The right answer depends on your circumstances and the tax year concerned.
