How do I know if I am owed a tax rebate?

Start with your tax code rather than your bank balance. Find the code on your most recent payslip and check whether it matches your circumstances: 1257L is the standard code for someone with one job and the full Personal Allowance. Codes such as BR, 0T, D0 or anything ending W1, M1 or X on your only job are the classic overpayment signals, as is a K code you cannot explain. Then check whether any of the ten trigger events applied to you in the last four years: a job started without a P45, two jobs at once, a benefit in kind that ended, stopping work mid-year, a pension lump sum, or Marriage Allowance never claimed.

Will HMRC tell me if I have paid too much tax?

Sometimes, but not reliably. HMRC reconciles PAYE records after the tax year ends and sends a P800 tax calculation letter where its figures show a discrepancy, and only to people who are employed or receive a pension. If the wrong information was in HMRC's records all along, for example a company car that ended but was never removed from your code, the year can reconcile cleanly to a wrong answer and no letter is generated at all. Treating "no letter" as proof you are not owed anything is the single most common reason overpayments go unclaimed.

How much is a typical tax rebate?

It depends entirely on which failure caused it. Losing your whole Personal Allowance to a BR code costs £2,514 a year at basic rate, at any basic rate salary. A company car benefit of £6,000 left in your code after the car went back costs £1,200 a year at basic rate. Marriage Allowance is £252 a year and up to £1,260 backdated in full. Uniform flat rate relief is more modest, around £12 a year on the standard £60 allowance at basic rate. Because claims reach back four years, several small items in the same claim frequently add up to more than any single year looks worth.

Is it too late to claim for old tax years?

Not yet, for anything from 2022/23 onward. The general time limit for a tax claim is four years from the end of the tax year concerned. As at August 2026 that leaves 2022/23, 2023/24, 2024/25 and 2025/26 open, plus the current 2026/27 year which is corrected through your tax code rather than claimed. The 2022/23 window closes on 5 April 2027 and cannot be reopened afterwards, so that is the year to check first even though it is the one you are least likely to have paperwork for.

Do I have to pay someone to claim a tax rebate?

No. Every claim route is free through HMRC: the online P800 claim service, your Personal Tax Account, the Check your Income Tax for previous years service, the Marriage Allowance application and the employment expenses service all cost nothing. Refund companies are legitimate businesses but they charge a percentage of your refund for making the same claim. RIFT, one of the larger UK firms, publishes a fee of 36% of your refund including VAT with a £60 minimum for a PAYE rebate. If a firm tells you a claim can only be made through them, that is not correct.

Tax Guides

Am I Due a Tax Rebate? 10 Signs You Have Overpaid HMRC

Ten specific situations that quietly cause overpaid tax, what each one is typically worth, and how to check every claimable year in under a minute. No letter required.

TapTax Team23 August 202612 min read

Key takeaways

Overpaid tax is almost always caused by an event, not by a mistake you made. Ten of those events are listed below
The single most expensive one is losing your Personal Allowance to a wrong code, which costs £2,514 a year at basic rate whatever your salary
Waiting for a P800 is not a test. HMRC only writes when its records disagree with themselves, and often they do not
You can look back four tax years, so 2022/23, 2023/24, 2024/25 and 2025/26 are all still open alongside the current year
Checking costs nothing and takes under a minute. Claiming through HMRC also costs nothing

£2,514

Annual cost of losing your allowance at basic rate

5 years

Current year plus 4 previous years

£1,260

Marriage Allowance backdated in full

Nobody wakes up wondering whether they overpaid income tax for no reason. The question almost always follows an event: a job change, a second job, a pension starting, a benefit ending, a partner giving up work. Those events are what break tax codes, and a broken code is what produces a rebate.

So the useful version of "am I due a tax rebate?" is not a feeling. It is a checklist. Here are the ten situations that reliably cause overpayment, what each is typically worth, and what to do about it.

Every figure is an estimate on published 2026/27 rest of UK rates and thresholds. Scottish and Welsh positions differ. Confirm your own position with HMRC.

Tax rebate: Income tax you paid above your actual liability for a tax year, returned to you. In HMRC's own language this is a refund or repayment. It is caused by the tax deducted through PAYE being calculated on wrong information, most often a tax code that gave you less tax free pay than you were entitled to.

1. You started a job without handing over a P45

If your new employer does not have your previous income and tax details, HMRC says "you'll be paid using an emergency tax code". Codes ending W1, M1 or X tax each pay period in isolation, as though you earned that amount every single period of the year.

On a steady salary from April this costs little. Start part way through the year and it costs a lot, because the months of unused allowance sitting behind you are ignored. A mid-October start on £32,000 typically overpays around £324 a month until the code is corrected.

Typically worth: £300 to £1,500, depending on when you started.

2. You had two jobs at once, even briefly

When you hold two employments, HMRC has to decide which one carries your Personal Allowance. It should be the higher paying one. When it lands on the smaller job, part of your allowance goes unused while your main income is taxed flat on a BR code at 20% from the first pound.

Being paid by an old and a new employer in the same month is on HMRC's own list of reasons a tax calculation letter gets issued. It is also one of the reasons a letter sometimes does not.

Typically worth: up to £2,514 a year at basic rate.

3. Your main job is on BR, 0T or D0

These codes are correct on a second income and expensive on your only one. BR taxes everything at 20% with no allowance. 0T removes the allowance and applies the normal bands. D0 taxes the lot at 40%.

Code on your main job	Salary	Estimated tax	Tax on the right code	Estimated overpayment
BR	£28,000	£5,600	£3,086	£2,514
0T	£60,000	£16,460	£11,432	£5,028
D0	£35,000	£14,000	£4,486	£9,514

Typically worth: £2,514 a year and up, per year it ran.

4. A company car, fuel or medical cover ended

Benefits in kind are collected as a deduction from your tax free allowance. When the benefit stops, the deduction should stop with it. Very often it does not, because nothing in the process forces anyone to remove it.

A £6,000 car benefit left in your code costs a basic rate taxpayer £1,200 a year and a higher rate taxpayer £2,400. Survive two years untouched and that is the whole rebate on its own.

Typically worth: £180 to £2,400 a year.

5. Your code has a K in it and you do not know why

A K code means your deductions exceed your allowance, so there is no tax free pay at all and an extra amount is added to your taxable income. K codes are sometimes exactly right. They are also the classic fossil of a benefit that ended years ago or an underpayment that was already settled.

Typically worth: varies widely. Always worth investigating.

6. You are married or in a civil partnership and one of you earns under £12,570

Marriage Allowance lets the lower earner transfer £1,260 of Personal Allowance to their spouse or civil partner. HMRC states it "reduces their tax by up to £252 in the tax year", where the lower earner's income is normally below £12,570 and the higher earner's is between £12,571 and £50,270.

Backdating currently reaches 6 April 2022. An eligible couple who never claimed can pick up £252 for each of 2022/23, 2023/24, 2024/25, 2025/26 and the current year: up to £1,260, for one online application by the lower earner.

Typically worth: up to £1,260 in total.

7. You stopped work part way through a tax year

Your Personal Allowance is spread evenly across the year by PAYE, on the assumption you keep earning. Stop in month five and you have paid tax as though seven more months of income were coming. It was not.

Redundancy, a career break, going travelling, moving to full-time study and maternity leave that runs past the end of company pay all produce this. If you stopped working and are not claiming benefits, form P50 exists for exactly this. If you left the UK, that is form P85.

Typically worth: hundreds to low thousands, depending on when you stopped.

8. You took a pension lump sum

The first flexible payment out of a pension pot is usually taxed on a month 1 basis, as though you were going to take that same amount every month for the rest of the year. On a one-off withdrawal that produces a large, temporary overdeduction.

There are three dedicated reclaim forms depending on your circumstances: P55 if you did not empty the pot, P53Z if you emptied it and are still working, and P50Z if you emptied it and stopped working.

Typically worth: often four figures on a substantial withdrawal.

9. You pay for things your job requires

Employees can claim tax relief on certain work costs, and most never do. The main ones are washing or replacing a uniform, replacing small tools, and professional fees or subscriptions to HMRC-approved bodies.

Uniform and tool relief is a flat rate rather than a refund of your spending. HMRC's flat rate expenses guidance sets an agreed amount per job, defaulting to £60 where your job is not listed, and explains that "if you claim a flat rate expense of £60 and pay tax at a rate of 20% in that year, you will pay £12 less tax". Some trades are far higher: joiners and carpenters are £140, ambulance staff on active service £185, cabin crew £720.

Professional fees work differently again and are relieved on what you actually paid, with receipts. Both reach back four years. See our guides to the uniform tax rebate and tools and union fees.

Typically worth: £60 to £700 of relief across five years.

10. You worked from home before April 2026 and never claimed

This one has a deadline attached. HMRC's working at home page now states: "From the tax year 6 April 2026 to 5 April 2027, you will not be able to claim tax relief for working from home. You can still claim for the 4 previous tax years."

So the current year is closed, and the four years behind it are not, and they close one by one. If you were required to work from home at any point since April 2022 and never claimed, that is a live claim with a clock on it. Our guide to claiming working from home tax relief covers the eligibility rules, which are stricter than most people assume.

Typically worth: roughly £62 to £140 per year claimed.

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How to check, rather than guess

The fastest test is the code itself. Find the tax code on your most recent payslip, then run it through our free tax code checker with your salary and circumstances. It tells you what your code should be, whether the one you are on matches, and roughly what any gap is worth per year. You can check every claimable year back to 2022/23 in the same pass.

It is an estimate designed to give you a number to take to HMRC, not a replacement for HMRC's own calculation.

If a P800 has landed, our guide to reading a P800 takes the letter apart line by line. If nothing has arrived, how to claim a tax refund from HMRC sorts you onto the right claim route, and the full reclaim guide walks the whole four-year recovery.

The deadline nobody mentions

The general time limit for a tax claim is four years from the end of the tax year concerned, which HMRC's Self Assessment Claims Manual traces to TMA 1970 s43.

As at August 2026 that means:

Tax year	Claim deadline	Status
2022/23	5 April 2027	Open, and closing first. Deal with this one
2023/24	5 April 2028	Open
2024/25	5 April 2029	Open
2025/26	5 April 2030	Open
2026/27	5 April 2031	In progress, fix the code instead

2022/23 is the year people are least likely to have paperwork for, and it is the year with the shortest runway. If any of the ten signs above applied to you that far back, start there.