How to Check if HMRC Owes You Money in 2026

If you're employed in the UK and your tax is taken straight from your pay each month, there's a strong chance HMRC owes you money.

Not might. Owes.

Millions of pounds in legitimate rebates go unclaimed every single year because most people don't know they're eligible, don't know how to check, or assume HMRC will just sort it out automatically. None of those assumptions are correct.

This guide explains exactly how to check whether HMRC owes you a rebate, how much you might be owed, and how to claim it back without writing a single letter or making a single phone call.

What is a PAYE tax rebate?

A PAYE tax rebate is money HMRC pays back to you because you've paid more income tax than you actually owed.

Every month, your employer deducts income tax from your pay using the PAYE system (Pay As You Earn). HMRC calculates how much tax you should pay based on your tax code, your earnings, and the personal allowance you're entitled to.

The problem is that the system doesn't account for everything. It doesn't know if you're paying to launder your uniform. It doesn't know if you've been using your own car for work and not being fully reimbursed. It doesn't know about your professional fees, your tools, or your working-from-home costs.

All of these things create allowances and reliefs you're entitled to claim. And every one of them, left unclaimed, means you've paid HMRC more tax than you legally needed to.

A tax rebate isn't a benefit. It isn't a loophole. It's your money, sitting with HMRC, waiting to be claimed back.

Who is most likely to be owed a rebate?

In theory, any PAYE worker can be owed a rebate. In practice, certain groups are more likely to have larger amounts sitting with HMRC.

You probably qualify for at least something if you:

• Are employed in the UK and pay tax through PAYE
• Have ever worn a uniform or specialist workwear for your job
• Have used your own tools, equipment, or materials for work
• Have worked from home for any part of any tax year since 2020
• Have driven your own vehicle for work and not been fully reimbursed
• Pay any professional fees, union dues, or subscriptions for your job
• Changed jobs partway through any tax year
• Have ever been on an emergency tax code

You almost certainly qualify if you:

• Work in healthcare (nurses, paramedics, care workers)
• Work in construction or any trade with site-to-site travel
• Work in transport (HGV, delivery, courier roles)
• Work in the emergency services
• Are an MOD or armed forces worker
• Work in the oil, gas, or offshore industry

Workers in these industries often have multiple categories of allowances. The combined rebates can be substantial, especially when claimed across four tax years at once.

What HMRC will not tell you

HMRC is the agency you pay your tax to. They are not the agency that proactively tells you when you have paid them too much.

This is the single most important thing to understand about UK tax rebates: the system is built around you knowing what you are owed and asking for it. HMRC will catch some obvious overpayments, like when an emergency tax code has been left running too long. They will issue a P800 calculation in those cases. But anything that involves an allowance you have not claimed, a work expense you have not declared, or a tax code error from years ago that nobody picked up at the time, will sit on your record indefinitely.

Common situations where HMRC will not refund you automatically:

• You have been entitled to a uniform allowance for years but never claimed it
• You used your own car for work but were reimbursed below the approved mileage rate
• You worked from home during the COVID years and never claimed the flat-rate relief
• You paid professional fees or union subscriptions out of your own pocket
• You were on an emergency tax code at the start of a new job
• You had multiple employers in one tax year and the personal allowance was split incorrectly
• You left a job partway through a tax year and didn't reclaim the unused personal allowance

None of these things will trigger an automatic refund. They sit in your records as overpaid tax. The money is yours, but you have to ask for it back.

Understanding your tax code

Your tax code is the simplest indicator of whether something might be wrong. It tells HMRC how much tax-free personal allowance to give you each pay period.

The standard tax code for the 2025/26 tax year is 1257L. The numbers represent your personal allowance divided by 10 (£12,570 ÷ 10 = 1,257). The letter indicates your circumstances.

Common tax codes and what they mean:

• 1257L: Standard code for someone with a single job and the basic personal allowance
• BR: All income from this source is taxed at basic rate. Often used for second jobs
• 0T: No personal allowance. Often applied when an employer doesn't have enough information
• D0: All income taxed at higher rate (40%)
• K codes: Indicate that adjustments are owed to HMRC (often for benefits or untaxed income)
• W1, M1, X: Emergency tax codes. Common at the start of a new job. Often left in place too long

If you have ever been on a W1, M1, X, BR, or 0T code when you shouldn't have been, you may have overpaid tax during that period. Specialist accountants check tax code history as part of every rebate review.

How much could you be owed?

The average UK PAYE tax rebate is around £3,500.

That number assumes you can claim across several tax years. It also assumes you have at least a couple of categories that apply to you (uniform plus mileage, for example, or working from home plus professional fees).

Typical rebate amounts by claim type:

The maths is straightforward. The more categories that apply to you, and the more years you can claim back, the larger your rebate. Workers who tick multiple boxes regularly see rebates well above the £3,500 average.

How to check if HMRC owes you money

There are three ways to check. They vary considerably in how much hassle they involve and how much you'll actually recover at the end.

Option 1: Check your personal tax account on GOV.UK

You can sign into your Personal Tax Account through GOV.UK to see your tax code, your earnings history, and whether HMRC has issued you a P800 calculation. A P800 is the letter HMRC sends when their own systems have flagged that you've over or underpaid tax.

This option is free but limited. The Personal Tax Account only shows you what HMRC has already identified. It won't tell you about the allowances you've never claimed, the work-related expenses you've never declared, or the years where you were overtaxed because of an emergency tax code that nobody flagged.

In short: useful for catching obvious overpayments. Useless for everything else.

Option 2: Submit your own claim using HMRC forms

If you know which allowances apply to you, you can submit a claim directly to HMRC using the P87 form. This is the form used for claiming work-related expenses for PAYE employees.

You can submit P87 forms online through your Government Gateway account or by post. You'll need to know exactly what to claim, in what amounts, for which tax years. HMRC's processing time for claims submitted this way is typically 8 to 12 weeks. If HMRC challenges the claim, you handle that yourself.

This option is free but requires real time, attention, and knowledge of UK tax law. Most people who try it either undershoot (claiming less than they're owed) or get the process wrong and have claims rejected.

Option 3: Use a specialist accountancy firm

The third option is to let a specialist accountancy firm handle the whole thing for you. This is where SmartRebate comes in.

We connect you with a regulated accountancy firm that processes over 1,700 rebate claims every single month. They specialise in identifying every allowance you're entitled to, calculating your exact rebate across all eligible years, and managing the entire HMRC process on your behalf.

Their success rate is over 90%. The typical timeline from applying to money in your bank account is 3 to 6 weeks. No win, no fee. The accountancy firm charges a fixed percentage of your rebate, deducted only when HMRC pays out. If the claim isn't successful, you pay nothing.

SmartRebate's own service is free. We're paid by the accountancy firm for the introduction, not by you.

How far back can you claim?

HMRC allows you to claim back up to four complete tax years, plus any unclaimed amounts in the current tax year.

As of 2026, that means you can claim for:

• 2021/22 tax year (deadline: 5 April 2026, closing soon)
• 2022/23 tax year (deadline: 5 April 2027)
• 2023/24 tax year (deadline: 5 April 2028)
• 2024/25 tax year (deadline: 5 April 2029)
• 2025/26 tax year (current)

If you've never claimed before and you've been working through PAYE the whole time, you could potentially have five years' worth of unclaimed rebates waiting for you. That window narrows every year. Once a tax year is closed, that money is gone for good.

If you've worked from home at any point during the 2021/22 tax year and you haven't claimed yet, you have until 5 April 2026 to do so. After that, the money is unrecoverable.

How long does it take to get paid?

This depends entirely on which route you take.

Doing it yourself through HMRC's portal: 8 to 12 weeks for HMRC to process, plus any time you spend gathering information, completing forms, and responding to queries. If HMRC asks for evidence or clarification, the timeline extends.

Using a specialist accountancy firm: typically 3 to 6 weeks from the point you submit your application. The firm handles all communication with HMRC. You don't deal with any of it directly.

Is there a cost to check?

No. Checking what you're owed costs nothing.

If you decide to use SmartRebate, our service is free. We're paid by the accountancy firm for the introduction. The accountancy firm operates on a no win, no fee basis. They take a fixed percentage of your rebate once HMRC pays out. If your claim isn't successful, nothing is owed.

There are no upfront fees, no admin charges, no application costs, no cancellation fees, and no hidden charges. The full customer-side cost is zero unless your claim succeeds and money lands in your account.

Common mistakes that cost people money

1. Assuming HMRC will refund you automatically

HMRC's own systems only catch obvious overpayments, like emergency tax codes left running too long. They don't know about your uniform, your tools, your home working, your mileage, or anything else that creates an allowance. If you don't claim, that money stays with HMRC.

2. Only claiming for one category

Most workers qualify for more than one allowance type. Claiming only the uniform allowance when you also work from home and pay professional fees leaves money on the table. A specialist accountant identifies every applicable category at once.

3. Missing the four-year window

You can only claim back four full tax years. Every April, the oldest year drops off. Workers who keep meaning to get round to it often end up forfeiting hundreds or thousands of pounds simply by leaving it too long.

4. Trying to navigate HMRC's forms alone

HMRC's P87 form looks simple but the rules behind it aren't. The flat-rate expenses list runs to dozens of industries, each with different allowances. Get the wrong amount or the wrong year and your claim either gets reduced or rejected.