The claim form that is wrong for most refunds

Figures relate to tax year 2025-26 (UK) · 2025 (US)

There is a short form for asking the IRS to give money back. It looks like the obvious answer whenever something has gone wrong.

Form 843 is that form, and most of the time it is the wrong one. It does not recover overpaid income tax, which is what people usually want back.

So the first question is never how to complete it. It is whether your problem belongs on it at all.

Key takeaways

• Form 843 claims refunds of certain taxes, penalties and interest.
• It is not the route for an overpaid income tax bill.
• Over-withheld social security is its classic use.
• Penalty abatement requests also belong on it.
• An amended return is what fixes income tax figures.
• There are separate deadlines depending on what you claim.
• One Form 843 covers one tax period and one issue.
• Attaching evidence matters more than the boxes you tick.

What is Form 843?

A general claim for refund or request for abatement. According to IRS guidance on the form, it covers certain taxes, interest, penalties, additions to tax and fees. You state what was charged, why it should not have been, and how much you want back. It is a short document carrying a long explanation.

Everything depends on the statement you attach rather than on the figures in the boxes.

A claim with no reasoning behind it comes back quickly and without much thought.

What can you not use it for?

Overpaid income tax, which is the single biggest misunderstanding. If your return showed too much tax because the figures were wrong, you amend the return rather than claim on this form. The same applies to missed credits, forgotten deductions and an exclusion you failed to claim at the time.

Our guide to amending a US return covers the right route for those cases.

Using the wrong form simply wastes several months before anybody tells you.

What is the classic expat use?

Social security and medicare that payroll should never have deducted. An American working for a British employer, or somebody the totalisation agreement covers, can find American payroll taxes coming out in error. Where the employer will not refund them, this form asks the IRS directly.

Our guide to certificates of coverage covers the agreement that prevents it.

That certificate stops the problem arising in the first place.

Do you have to ask the employer first?

Yes, and you have to show that you did. The IRS expects the employer to correct the error if they can, so a claim normally needs a statement that you asked and they refused, or that the employer has gone. That requirement catches people who skip straight to the form itself.

Keep the email in which you asked and whatever reply came back, however unhelpful.

Without that exchange the claim usually stalls before anybody reaches the merits.

Can you claim penalty abatement on it?

Yes, and this is its other main use. Where the IRS has charged a penalty and you believe reasonable cause applies, this form asks them to lift it. A letter can also settle many penalties, so the form is not always necessary.

Our guide to reasonable cause penalty relief covers the argument itself.

The strength of your explanation decides this far more than the format does.

A worked example

Take an illustrative example. An American in Edinburgh works for a British company that also runs a small American payroll.

An administrative error puts her on the American payroll for a year, and payroll deducts $7,400 of social security and medicare.

The totalisation agreement covers her, so she should have paid British National Insurance only, which she also paid.

The employer cannot unwind a closed payroll year, so she asks them in writing, keeps the refusal, and claims the $7,400 back directly.

Which form for which problem

What about interest the IRS charged?

The IRS rarely lifts interest, because it compensates for the time the money was outstanding. The exception covers interest arising from an unreasonable IRS error or delay, which is narrow but real. Claims on that ground need you to document the delay rather than merely assert it.

Dates of letters, telephone calls and responses are what make an argument like this work.

In our practice these succeed only where somebody kept a contemporaneous log.

What is the deadline?

Generally three years from filing the return or two years from paying the tax, whichever is later. For penalties the clock usually runs from payment. Somebody abroad who learns about an error late can find the window has closed while the post was travelling.

Our guide to the statute of limitations covers how the periods work.

Work out the deadline before you start gathering documents.

Can one form cover several years?

No, and this is a common reason claims come back. Each tax period and each type of claim needs its own form, so three years of wrongly deducted payroll tax means three separate submissions. You can post them together, but you cannot combine them into one.

Number them clearly and send them in one envelope with a covering letter listing the contents.

That makes it far less likely that one of them goes astray.

How do you file it from Britain?

By post, because no electronic route exists for this claim. You send it to the service centre the instructions name, which depends on what you claim. From abroad that means international post, so proof of posting matters more than usual.

Our guide to the IRS online account from the UK covers what you can and cannot do online.

Keep a complete copy of everything you send, including the envelope details.

How long does it take?

Months rather than weeks, and often longer from overseas. Six months is unremarkable, and a year is not unusual where a specialist unit has to review it. Chasing before several months have passed achieves almost nothing.

Diarise a follow up rather than checking repeatedly in the first few months.

An adviser with authority on file can chase it far more effectively than you can.

Does an adviser need authority?

To discuss it with the IRS, yes, and that takes weeks to process on its own. Filing the authority alongside the claim leaves nobody able to chase it for the first month or two. Doing it first is the more sensible sequence.

Our guide to Form 2848 and IRS authority covers the paperwork.

Put the authority on record before the claim goes anywhere.

What if your employer was American?

Then the error is more common and the fix is often easier. A US employer running payroll for somebody working in Britain may deduct out of habit, and payroll departments can usually correct the current year themselves. Closed years are where this form becomes necessary.

Our guide to working remotely for a US employer covers the payroll position.

Raising it in January is far easier than raising it in December.

What about shadow payroll arrangements?

These produce the error regularly, because two payrolls are reporting one person. Two payrolls can duplicate deductions or apply them in the wrong country, and nobody notices until somebody prepares the returns. The claim then has to untangle which country actually received what.

Our guide to shadow payroll between the US and UK covers the structure.

Reconciling both payslips side by side is the only reliable way to see it.

Does it apply to self-employment tax?

It can, where you paid self-employment tax although a totalisation certificate covered you. Amending the return often handles it better, because the return calculates self-employment tax. Which route applies depends on how the money reached the IRS in the first place.

Our guide to self-employment in the UK as an American covers the charge.

Take advice before choosing, because the two routes have different deadlines.

What evidence should you attach?

Everything that proves the charge was wrong and that you tried the obvious remedy first. Payslips, the certificate of coverage, correspondence with the employer and a clear calculation all help. A claim asking the IRS to work out your position for you rarely succeeds.

Set the numbers out in a short schedule rather than leaving them inside a narrative.

Anything a reviewer must calculate themselves slows the claim considerably.

What happens if it is refused?

You receive a notice explaining why, and appeal rights follow from there. Many refusals turn on a missing document rather than on the substance, so read the reason carefully first. Resubmitting with the gap filled often settles it.

A route to court also exists for a refund claim, though it rarely suits small amounts.

Check the deadline on the refusal letter the day it arrives.

Does HMRC have an equivalent?

Overpayment relief does a similar job on the British side, with its own four year window. The two systems run separately, so recovering money in one does nothing about the other. Somebody taxed twice usually runs both claims in parallel.

Our guide to overpayment relief for US filers covers the British claim.

Two authorities, two claims, two separate timetables to track.

Is it worth claiming small amounts?

Often not, once you price the time involved. A claim takes real effort to assemble and months to resolve, so a few hundred dollars may not justify the work. Payroll tax deducted in error usually runs to four figures, which changes the calculation entirely.

Work the amount out properly before deciding, because people frequently underestimate it.

A full year of payroll error rarely stays as small as it first appears.

What records should you keep?

The claim itself, proof of posting, the employer correspondence and every payslip for the period. Any later question turns on those four. Keep them until the claim finishes, and for several years afterwards.

Scan everything before posting, because international mail occasionally loses things.

Rebuilding a payroll year from memory is effectively impossible.

Does Form 843 help with a state tax problem?

Not at all, because it is a federal form and states run their own refund machinery. A California or New York overpayment needs that state's own claim, on its own timetable and with its own evidence rules. Americans who left a high tax state frequently have both problems running at once and have to pursue them separately.

Our guide to state tax after you leave covers the state side.

So a federal success tells you nothing about what the state will do.

What if the IRS keeps the money against another debt?

Then the refund can be offset rather than paid out, which surprises people who expected a cheque. Where you owe tax for another year, a successful claim may simply reduce that balance instead. That is still worth having, but it changes what you should expect to arrive.

Our guide to IRS payment plans from abroad covers managing an existing balance.

Check your account position before assuming money will reach your bank.

Can you file Form 843 while a return is outstanding?

You can, though unfiled returns tend to slow everything down. The IRS is reluctant to pay money out to somebody whose filing history has gaps, and a reviewer may simply hold the claim until the position is clear. Bringing the returns up to date first usually produces a faster answer overall.

Our guide to the streamlined route back covers catching up.

A clean filing record removes the easiest reason to park your claim.

Is there a minimum amount worth claiming?

No formal threshold exists, so the question is purely practical. Assembling the evidence, posting internationally and chasing for months all cost something, and a very small claim rarely repays that effort. The judgement is yours, but work out the real figure first rather than guessing at it.

Add up every affected payslip before deciding the amount is too small to bother with.

People routinely discover the total is several times what they assumed.

What goes in the explanation box?

A short, factual account in plain order: what happened, why the charge was wrong, what you did about it and what you now want back. Reviewers read a great many of these, so a claim that answers those four questions in that sequence gets dealt with faster than one that tells the story chronologically from the beginning.

Put the amount you are claiming in the first line rather than at the end.

Anything longer than a page usually means the schedule is doing too little work.

How to make a Form 843 claim

1. Check first whether an amended return is actually the right route.
2. Work out the deadline for the period you are claiming.
3. Ask the employer to correct it and keep their reply.
4. Prepare one form for each tax period and each issue.
5. Attach a short schedule showing exactly how the figure arises.
6. Include the certificate of coverage or other supporting evidence.
7. Put your adviser authority on record before you file.
8. Post it with proof, and diarise a chase several months out.

Mistakes and penalties we see with Form 843

The first is using it for overpaid income tax, when an amended return is the only route that works.

The second is claiming without first asking the employer, which the IRS expects you to have done.

The third is putting several years on one form, so the whole bundle comes back untouched.

The fourth is filing close to the deadline from abroad, where postal time alone can take you past it.

How US UK Tax Accountants helps

We start by checking which form your problem actually belongs on, because the commonest reason these claims fail is that they should have been an amended return instead.

Then we assemble the evidence in the order a reviewer reads it. Our US federal returns service covers the filings behind it.

If American payroll tax has been deducted while you worked here, get in touch before the window closes.

Last reviewed 24 October 2026. This article is general information and not personal tax advice, and claim procedures change over time.