Could HMRC owe you money? Check in 60 seconds

How this refund checker works

The checker above asks four quick things: whether you are employed under PAYE, whether you are married or in a civil partnership, whether you work under the Construction Industry Scheme (CIS), and what kind of job you do. From those answers it flags which of nine common refund types could apply to you, puts a realistic estimate against each one, and links you straight to the right claim route. Nothing you type is stored and nothing is sent to HMRC. Think of it as a triage tool: it tells you which claims are worth ten more minutes of your time, and which do not apply to you at all.

The nine checks it runs are: a wrong or emergency tax code, working-from-home relief, uniform and tools relief (the P87 route), mileage allowance relief, Marriage Allowance, CIS deduction refunds, higher-rate pension relief, higher-rate Gift Aid relief, and the P50 refund when you stop work part-way through a tax year. Each one has its own rules and its own form, which is exactly why so many go unclaimed: nobody at HMRC is tasked with telling you about them.

What each refund is worth in 2026/27

Values vary with your income and tax rate, but these are the typical amounts for a basic-rate taxpayer. Remember that most claims can be backdated to cover the current tax year plus the previous four, so the first claim you ever make is often worth five years at once.

A worked example: two very different refunds

Take Maya, a nurse on £30,000 who is married to a partner earning £11,500. She launders her own uniform, so she qualifies for the nurses' flat-rate expense of £125 a year, worth £25 a year in tax back at 20%. Claimed for the current year plus four back years, that is £125. Because her partner earns under the £12,570 Personal Allowance and Maya pays basic rate, the couple also qualify for Marriage Allowance: her partner transfers £1,260 of allowance, cutting Maya's tax by £252 this year, and the backdated years add roughly £1,000 more. Two small forms, around £1,375 recovered, and the £252 and £25 then repeat every year without her lifting a finger again.

Now take Dan, a CIS subcontractor who invoiced £38,000 in the year. His contractors deducted 20% at source, so £7,600 went to HMRC before he saw a penny. But CIS deductions ignore expenses. Dan spent £6,000 on materials, tools, mileage and insurance, so his actual profit is £32,000. His real bill for 2026/27 is £3,886 of Income Tax (20% of the £19,430 above his Personal Allowance) plus £1,165.80 of Class 4 National Insurance at 6%, a total of £5,051.80. He has already paid £7,600, so filing his Self Assessment triggers a refund of £2,548.20. This is why CIS refunds are routinely the biggest item this checker finds. Our self-employed tax calculator will run your own numbers in a minute.

Common mistakes that shrink or kill refunds

• Missing the four-year deadline. A claim for the 2022/23 tax year expires on 5 April 2027. Every April, another year of refunds becomes unclaimable forever.
• Confusing choosing to work from home with being required to. The £6 a week relief only applies where the job itself requires home working; hybrid working by choice does not qualify.
• Assuming your tax code is HMRC's problem. It is legally your responsibility to check it. Emergency codes after a job change, and codes that still carry old benefits-in-kind, quietly overtax millions. Run yours through the tax code checker.
• Forgetting professional fees. Registration fees and subscriptions to HMRC-approved bodies (nursing registration, trade bodies, unions with approved agreements) attract the same relief as uniforms and are claimed on the same P87.
• Signing with a refund agent. Agents routinely keep 25% to 30%, and some deeds of assignment capture future refunds too. Every claim on this page is free to make yourself.
• Not keeping CIS statements and expense records. Your refund is only as good as the paperwork behind it, so keep contractor deduction statements and receipts for the full year.

How HMRC actually pays you back

The route your money takes depends on the type of claim. For PAYE overpayments, HMRC usually issues a P800 calculation after the tax year ends, and you can then request the money into your bank account through your Personal Tax Account, typically arriving within about five working days, or wait for a cheque, which takes several weeks. For in-year problems such as a wrong tax code, the fix is usually a corrected code, which means the refund arrives spread through your remaining payslips rather than as a lump sum. Work-expense claims for earlier years generally come as a lump sum; claims for the current year are normally given through your tax code instead. CIS and Self Assessment refunds are repaid after you file, and filing early in April rather than waiting until January gets subcontractors their money up to nine months sooner.

One quiet warning: if a refund letter or text arrives out of the blue promising money and asking for card details, it is a scam. HMRC never asks for bank details by text or email; genuine repayments are claimed from inside your Personal Tax Account.

How to claim, step by step

1. Run the checker above and note which refunds it flags for you.
2. Firm up the numbers with the matching TaxFly tool: the Marriage Allowance calculator, the work expense rebate calculator for uniforms, tools, mileage and professional fees, or the tax code checker.
3. Claim directly with HMRC. Work expenses go through the online P87 route, Marriage Allowance has its own application, tax code fixes go through your Personal Tax Account, and CIS refunds come out of your Self Assessment. The official starting point for most of them is gov.uk/claim-tax-refund.
4. Once any refund lands, sanity-check your ongoing position with the take-home pay calculator so the same overpayment does not creep back next year.

Most claims take five to twenty minutes. HMRC typically repays within a few weeks, either through your tax code, a bank transfer, or a cheque.

This page is guidance and the figures are estimates only; always confirm your position and claim through GOV.UK or HMRC directly.