Most people assume HMRC only ever takes money — never gives it back. That’s not quite true. Every year, millions of pounds in overpaid tax sits unclaimed because people don’t realise they’re owed it, don’t know how to check, or assume it’s not worth the hassle.
It usually is worth the hassle. Refunds can run into hundreds of pounds, sometimes more, and checking takes less time than you’d think. The tricky part is knowing where to look, because HMRC doesn’t send out a friendly email saying “here’s your money” — you often have to go and find it yourself.
This article walks through the main ways people end up owed money, how to check each one, and what to watch out for — including the tax refund scams that specifically target people doing exactly this kind of search.
Why you might be owed money in the first place
Tax in the UK mostly runs on a system called PAYE (Pay As You Earn), where your employer deducts income tax and National Insurance automatically before you’re paid. It’s designed to get your tax roughly right across the year — but “roughly” is the key word.
Overpayments happen for ordinary, unglamorous reasons:
- You changed jobs partway through the tax year and were briefly on the wrong tax code
- You had two jobs at once and got taxed as if each was your only income
- You stopped working partway through the year but tax was calculated as if you’d work the whole year
- You were put on an emergency tax code and it was never corrected
- You paid for work expenses yourself (uniforms, tools, mileage, professional fees) and never claimed tax relief
- You’re eligible for Marriage Allowance and never applied
None of these are unusual. They’re the kind of thing that happens to completely ordinary people with completely ordinary jobs.
Check your tax code first
Your tax code is the short combination of numbers and letters (like 1257L) that tells your employer how much of your income to tax. It’s the single biggest cause of over- or under-payment, and almost nobody checks it.
You can find your tax code on your payslip, your P60, or by logging into your personal tax account on gov.uk. Compare it to what you’d expect given your personal allowance (the amount you can earn tax-free before income tax kicks in — £12,570 for most people in the 2026/27 tax year).
If your tax code looks wrong — say it has “BR”, “0T”, or “D0” on it when it shouldn’t — that’s often a sign you’ve been taxed incorrectly, sometimes for months without noticing.
Check for a P800 or Simple Assessment letter
If HMRC’s own systems spot that you’ve paid the wrong amount of tax, they sometimes write to you automatically. This usually happens after the tax year ends in April, once HMRC has reconciled everyone’s records.
Two letters to look out for:
- P800 — tells you whether you owe tax or are due a refund, based on HMRC’s calculation
- Simple Assessment letter — similar idea, usually sent when your tax situation is a bit more complex
If you’ve received one of these and ignored it, or moved house and never got it, log into your personal tax account to check your tax calculations for previous years. Refunds identified this way can sometimes be claimed online directly through your account, which is faster than waiting for a cheque in the post.
Check if you’re due Marriage Allowance
This one is worth a specific mention because take-up is low and eligibility is fairly broad.
Marriage Allowance lets one partner transfer £1,260 of their personal allowance to a spouse or civil partner, as long as:
- One of you earns below the personal allowance (£12,570)
- The other is a basic rate taxpayer (earning between roughly £12,571 and £50,270)
If eligible, it can reduce the higher-earning partner’s tax bill by up to £252 a year — and you can backdate a claim for up to four previous tax years, potentially worth over £1,000 in one go if you’ve never claimed before.
You apply directly through gov.uk’s Marriage Allowance service — it’s free, and only one person in the couple needs to apply.
Check if you’ve overpaid on savings interest or pension withdrawals
Two less obvious areas:
Savings interest. Banks no longer deduct tax automatically from savings interest for most people, but if you have a lot of savings across several accounts, it’s possible tax has been miscalculated — particularly if your income changed during the year. Check your P800 or Simple Assessment for any mention of savings interest.
Pension withdrawals. If you’ve taken a lump sum from a pension — particularly a first withdrawal — you’re often taxed using an “emergency” tax code that assumes you’ll take that same amount every month for the rest of the year. This routinely results in significant overtaxation. If this applies to you, you can either wait for HMRC to correct it automatically (can take months) or fill in one of the P50Z, P53Z, or P55 forms to claim it back faster, depending on your situation.
The comparison: which situation applies to you?
| Situation | How to check | How to claim |
|---|---|---|
| Wrong tax code | Personal tax account or payslip | HMRC corrects going forward; refund for past overpayment via P800 |
| Received a P800/Simple Assessment | Check post or personal tax account | Often claimable online through your account |
| Never claimed Marriage Allowance | Check eligibility on gov.uk | Apply online, backdate up to 4 years |
| Unclaimed work expense tax relief | Check if you’ve paid for uniforms, tools, mileage, subscriptions | Claim via P87 form or self-assessment |
| Overtaxed pension lump sum | Check payslip/pension statement for emergency tax code | P50Z, P53Z, or P55 form depending on circumstances |
| Left a job mid-year | Check final payslip and P45 | May self-correct, or claim via personal tax account |
The common misconception: “If I was owed money, HMRC would just send it to me”
This is the assumption that stops most people from ever checking. It’s only partly true.
HMRC’s automatic systems do catch some overpayments — that’s what the P800 letters are for. But they don’t catch everything, and they definitely don’t catch things like unclaimed Marriage Allowance or unclaimed expense relief, because those depend on you telling HMRC something they don’t otherwise know.
There’s also a time limit. You can generally only claim tax refunds going back four tax years. After that, the money isn’t recoverable — HMRC isn’t obligated to give it back once that window closes. So “they’ll get round to it eventually” isn’t a safe assumption. If you think you’re owed money from several years ago, the clock is genuinely running.
Watch out for tax refund scams
Searching for “how to check if you’re owed money from HMRC” is exactly the kind of thing scammers target, because it means you’re actively expecting a refund — which makes a fake “you’re due £280, click here” text or email far more convincing.
A few rules that hold every time:
- HMRC will never text or email you asking you to click a link to claim a refund
- HMRC will never ask for your bank details, PIN, or password by email or text
- Genuine refunds are claimed by logging into your account directly at gov.uk (typed in yourself, not via a link) — not through a link in a message
If you get a message like this, don’t click anything. You can report suspicious contact directly to HMRC through the gov.uk phishing and scams guidance.
The bottom line
- Log into your personal tax account on gov.uk this week and check your tax code against what you’d expect — it’s the fastest way to spot a problem
- If you’ve had a P800 or Simple Assessment letter in the last four years and never followed up, go back and check it — the claim window doesn’t stay open forever
- If you’re married or in a civil partnership and one of you earns under £12,570, check Marriage Allowance eligibility — it’s a straightforward win most couples never claim
- If you took a pension lump sum recently and it felt heavily taxed, it probably was — check your tax code on that payment specifically
- Never respond to a text or email claiming to be HMRC about a refund — go to gov.uk directly and check from there instead
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