UK Tax Refund 2026: How to Claim Back from HMRC

Most UK taxpayers overpay tax at some point — whether through an incorrect tax code, emergency tax on a new job, unclaimed work expenses, or simply paying too much on account through Self Assessment. The good news: claiming a refund from HMRC is usually straightforward, completely free, and can be done online in minutes. This guide walks you through the most common refund scenarios, how much you might be owed, how to claim, and crucially how to avoid the refund-chasing companies that take 30–50% of money that's rightfully yours.

Who's entitled to a tax refund?

You're likely owed money back if:

You've been on the wrong tax code — perhaps your employer used an emergency code (1257L W1/M1) when you started, or HMRC didn't know about your Personal Allowance.
You changed jobs mid-year — your new employer may have assumed you'd been earning all year, pushing you into a higher tax bracket temporarily.
You're self-employed and overpaid on account — Self Assessment asks you to pay tax in advance based on last year's profit; if this year was quieter, you've overpaid.
You've paid for work expenses out of pocket — uniforms, professional subscriptions, tools, mileage, or working-from-home costs that your employer didn't reimburse.
You're married or in a civil partnership and one of you earns under £12,570 while the other is a basic-rate taxpayer — Marriage Allowance can be backdated four years.
You're a subcontractor under CIS — builders, tradespeople and others often have 20% or 30% deducted at source and are due a refund once expenses are accounted for.
You're a higher or additional-rate taxpayer with a pension — you only get basic-rate relief automatically; you must claim the rest yourself.

HMRC doesn't always know your full circumstances, so refunds rarely arrive unsolicited. You need to tell them.

The six most common UK tax refund scenarios

1. PAYE overpayment (the P800 tax calculation)

What it is: If you're employed or receive a pension through PAYE, HMRC reconciles your tax each year after 5 April. If you've overpaid, they send a P800 tax calculation telling you how much is owed.

Why it happens:

Wrong tax code (common after starting a new job, returning from maternity leave, or receiving taxable benefits).
Emergency tax — the 1257L W1 or M1 code taxes each pay period in isolation, ignoring your cumulative Personal Allowance of £12,570.
Multiple jobs or pensions where tax codes weren't coordinated.

How much? Typical refunds range from £200 to £800, though we've seen cases over £2,000 where emergency tax ran for months.

How to claim: HMRC usually sends the P800 automatically between June and November. If it says "We owe you," you can claim online via your Personal Tax Account at gov.uk, or HMRC will send a cheque. Processing takes 5–8 weeks on average.

Proactive claiming: If you think you've overpaid but haven't received a P800, you can request a review by calling HMRC or updating your tax code through your Personal Tax Account. Don't wait — you can backdate claims for four tax years.

2. Self Assessment overpayment

What it is: If you file a Self Assessment return and the tax calculated is less than what you've already paid (either through PAYE, payments on account, or CIS deductions), HMRC owes you a refund.

Why it happens:

Payments on account — if you're self-employed, HMRC asks you to pay half your previous year's tax bill by 31 January and the other half by 31 July. If your profit dropped this year, you've overpaid.
First year of self-employment — you might have made payments on account based on an estimate that turned out too high.
CIS deductions — subcontractors have tax deducted at source (20% or 30%); once you account for expenses on your return, you often get a chunk back.

How much? First-year sole traders sometimes see refunds of £1,000–£3,000. CIS workers typically reclaim £2,000–£3,000 once legitimate business expenses (van, tools, fuel, insurance) are deducted.

How to claim: File your Self Assessment return online by the deadline (31 January for the previous tax year). HMRC calculates any refund automatically. You'll be asked for your bank details if they don't have them. Refunds usually arrive within 2–4 weeks of filing, though it can take up to eight weeks in busy periods.

Top tip: If you know your profit will be lower next year, you can apply to reduce your payments on account using form SA303. This avoids overpaying in the first place.

3. Employment expenses (form P87)

What it is: If you've paid for things you need to do your job — and your employer hasn't reimbursed you — you can claim tax relief. You don't get the full cost back; you get the tax you paid on that amount.

Common claimable expenses:

Uniforms and tools — if you're required to wear branded clothing or buy your own tools (mechanics, chefs, construction workers).
Professional subscriptions — annual fees for bodies on HMRC's approved list (engineers, nurses, teachers, accountants, etc.).
Mileage — if you use your own car for work travel (not commuting), you can claim 45p per mile for the first 10,000 miles, 25p thereafter. If your employer pays less, you claim relief on the difference.
Working from home — if your contract requires you to work from home regularly, you can claim £6 per week (£312 per year) without receipts, or the actual additional costs (heating, lighting, internet) if higher.

How much? If you claim £1,000 of expenses and you're a basic-rate (20%) taxpayer, you get £200 back. Higher-rate (40%) taxpayers get £400. The relief is given by adjusting your tax code or as a lump sum.

Limits: You can claim up to £2,500 per year using the simple P87 form. If your expenses exceed that, you'll need to file a Self Assessment return instead.

How to claim: Complete form P87 online via gov.uk (search "Claim tax relief for your job expenses"). You'll need details of what you spent and evidence if asked (receipts, mileage logs). Processing takes 8–12 weeks. You can backdate claims for four tax years.

Example: Raj is a community nurse paying £250/year for his RCN membership. He's a higher-rate taxpayer. He claims four years: £250 × 4 = £1,000 expenses. Tax relief = £1,000 × 40% = £400 refund.

4. Marriage Allowance backdate

What it is: If you're married or in a civil partnership, and one of you earns less than the Personal Allowance (£12,570 in 2026–27) while the other is a basic-rate taxpayer, the lower earner can transfer £1,260 of unused allowance. This saves the higher earner up to £252 per year.

How to claim: Apply online at gov.uk/marriage-allowance. You can backdate for four tax years if you were eligible but didn't claim — that's over £1,000 in total. HMRC adjusts the recipient's tax code going forward and sends a cheque or bank transfer for previous years. Processing takes 4–8 weeks.

Who can't claim: If the higher earner pays higher-rate (40%) or additional-rate (45%) tax, Marriage Allowance doesn't apply. Consider transferring assets or pension contributions instead.

5. CIS (Construction Industry Scheme) reconciliation

What it is: If you're a subcontractor — builder, electrician, plumber, plasterer — your contractor deducts tax at source (20% if you're registered, 30% if not) and pays it to HMRC on your behalf.

Why refunds happen: CIS deductions assume you have little or no expenses. In reality, subbies have significant costs: van lease or purchase, fuel, tools, PPE, insurance, materials (sometimes), phone. Once you file a Self Assessment return and deduct these allowable expenses, your actual tax bill is often much lower than what's been deducted.

How much? A typical CIS refund is £2,000–£3,000, though we've seen £5,000+ for those with high deductions and substantial expenses.

How to claim: File a Self Assessment return (you're legally required to if you're self-employed). Include all CIS deductions (shown on your monthly statements) and claim all allowable business expenses. HMRC calculates the refund automatically.

Top tip: Keep every receipt. Fuel, tools, work clothing, van costs, and even a portion of your home bills (if you do admin at home) are all claimable. Use the AI Tax chat or AI Accountant service if you're unsure what counts.

6. Pension higher-rate and additional-rate relief

What it is: When you pay into a personal or workplace pension, you get tax relief. Basic-rate relief (20%) is usually added automatically by your pension provider. If you're a higher-rate (40%) or additional-rate (45%) taxpayer, you must claim the extra 20% or 25% yourself.

Example: Priya earns £60,000 and pays £5,000 into her pension (net contribution £4,000; her provider adds £1,000 basic relief = £5,000 gross). She's a higher-rate taxpayer on £47,430 of her income (the slice above £12,570 up to £50,270, plus £10,000 above that). She can claim an extra 20% on the £5,000 gross contribution = £1,000. This is given by extending her higher-rate threshold, reducing her tax bill by £1,000.

How to claim: Include pension contributions on your Self Assessment return, or call HMRC to adjust your tax code if you're employed and not in Self Assessment. You can backdate for four tax years.

How long do refunds take?

| Refund type | Typical timeline | |-------------|------------------| | P800 (PAYE) | 5–8 weeks from P800 issue | | Self Assessment | 2–4 weeks after filing (up to 8 weeks in Jan/Feb) | | P87 (employment expenses) | 8–12 weeks | | Marriage Allowance | 4–8 weeks | | CIS via Self Assessment | 2–4 weeks after filing |

HMRC pays by bank transfer if they have your details, otherwise by cheque to your registered address.

Common mistakes (and how to avoid them)

Using a refund agent and losing 30–50% in fees. HMRC never charges you to claim your own refund. Third-party companies are legal but take a huge cut of money you could claim yourself for free in 20 minutes. If you'd rather not DIY, use a fixed-fee service like AI Accountant — you keep all your refund.
Missing the four-year deadline. You can backdate most claims four tax years. For 2026–27, that means back to 2022–23. After that, it's gone.
Not keeping records. If you're claiming expenses, HMRC can ask for evidence. Keep receipts, bank statements, mileage logs for at least six years (five years after the 31 January filing deadline).
Assuming HMRC will tell you. They send P800s automatically, but only if they have complete information. If you've changed address, switched jobs, or have multiple income sources, they might not know. Check your Personal Tax Account regularly.
Claiming expenses you're not entitled to. Commuting costs, lunches, everyday clothing — these aren't allowable. Only claim what you genuinely need because of your job and wouldn't otherwise buy.
Forgetting to update your tax code. If you've claimed expenses or Marriage Allowance, HMRC should adjust your code going forward. Check your next payslip to make sure it's applied — if not, call them.

How to claim: step-by-step

For PAYE refunds (P800):

Wait for your P800 letter or check your Personal Tax Account online (gov.uk/personal-tax-account).
If it says you're owed money, follow the link to claim online, or wait for a cheque.
If you think you've overpaid but no P800 has arrived, call HMRC on 0300 200 3300 or use the online contact form.

For Self Assessment refunds:

Register for Self Assessment if you haven't already (gov.uk/register-for-self-assessment).
File your return online by 31 January following the end of the tax year.
HMRC calculates any refund automatically. Provide your bank details when prompted.

For employment expenses (P87):

Go to gov.uk/tax-relief-for-employees/how-to-claim.
Sign in with your Government Gateway ID.
Complete the P87 form, listing expenses and amounts.
Submit. HMRC will contact you if they need evidence.

For Marriage Allowance:

Go to gov.uk/marriage-allowance.
Check you're eligible (one earns under £12,570, the other is a basic-rate taxpayer).
The lower earner applies online. You'll both need your National Insurance numbers.

For CIS refunds:

Register for Self Assessment.
File your return, including all CIS deductions from your monthly statements and all allowable expenses.
HMRC calculates and pays your refund.

What to do next

If your situation is straightforward — a single P800, a simple expense claim — claim directly via gov.uk for free. It takes 20 minutes and you keep every penny.

If you're unsure what you're owed, have multiple years to backdate, or just want someone else to handle it, chat with AI Tax at myaitax.info for instant answers to specific questions, or hand the whole thing over to AI Accountant (myaiaccountant.info) for end-to-end handling at a fixed fee. You'll still keep your full refund — no percentage taken.

Whatever you do, don't ignore money that's yours. HMRC holds billions in unclaimed refunds. Check your tax position once a year, keep records, and claim what you're owed. The process is simpler than you think, and the average refund pays for a nice holiday or a chunk off your credit card.

UK Tax Refund Guide 2026: How to Claim Money Back from HMRC