The short version
If your tax code is wrong, or you've been on emergency tax, you may have paid HMRC more than you owed — and you can get it back. HMRC often spots it and posts you a P800 saying you're due a refund, but you can also check yourself any time in your free HMRC account.
Claiming directly is free and quick — you keep every penny. Two rules keep you safe: never click a "tax refund" link in a text or email, and never pay a company a cut to claim what you can claim yourself.
Income Tax is mostly collected through PAYE — your employer or pension provider deducts it from each payslip using a tax code sent by HMRC. When that code doesn't match your real situation, the wrong amount comes off. Across a year that can add up to hundreds of pounds you didn't owe — money that's sitting waiting for you to claim.
Why people overpay tax
You don't have to have done anything wrong. The most common reasons HMRC ends up holding too much of your money:
- Emergency tax on a new job — if you start work without a P45, your employer may use an emergency code that ignores part of your allowance, so too much tax comes off until HMRC sends the right code.
- Stopping work part-way through the year — your tax-free allowance is spread across the whole year, so if you leave a job (or retire) mid-year, you may have paid tax as if you'd earn for all 12 months.
- More than one job or pension — a second job is often put on a BR code (all taxed at 20%), which can be too much if your main job hasn't used up your allowance.
- A company benefit changed — for example a car or medical insurance ending, leaving your code too low.
- Tax relief you never claimed — for example working-from-home costs, washing a required uniform, tools, or professional fees and subscriptions. Many people simply never claim these.
You can also underpay, in which case the P800 or a Simple Assessment will ask you to pay the difference — but for most PAYE workers who've had a code change, the surprise is a refund.
What your tax code means
Your tax code is on your payslip, P60 or P45, and in your HMRC account. The number is your tax-free allowance with the last digit removed; the letters describe your situation. For 2026/27 the standard code is 1257L — the 1257 reflects the £12,570 Personal Allowance, which has been frozen until at least 2028, so 1257L stays the normal code.
| Code | What it means |
|---|
| 1257L | The standard code — you get the full £12,570 tax-free allowance. Most people with one job or pension. |
| L | You're entitled to the standard tax-free Personal Allowance. |
| BR | All income from this job/pension taxed at the basic rate (20%) — usually a second job or pension. Can mean overpayment if your allowance isn't all used. |
| D0 / D1 | All income from this source taxed at the higher rate (40%) / additional rate (45%) — usually a second job/pension. |
| 0T | Your allowance has been used up, or you've started a job and your employer doesn't have your details yet. A common over-taxation flag. |
| NT | No tax is being taken from this income. |
| K | You have untaxed income greater than your allowance (e.g. owed tax or a benefit). The calculation works differently. |
| W1 / M1 / X | Emergency code. Tax is worked out on that week's or month's pay alone, ignoring earlier months — so you can be over-taxed until HMRC sends the right code. |
| S… / C… | An S prefix means Scottish rates; a C prefix means Welsh rates (e.g. S1257L, C1257L). |
Spot an emergency code?
If your code ends in W1, M1 or X — or you see BR or 0T when your situation is straightforward — it's worth checking. Emergency codes are normal for a few weeks when starting a job, but if one sticks, you can ask HMRC to fix it, and reclaim anything overpaid.
The P800 and Simple Assessment
After each tax year ends (5 April), HMRC checks whether your PAYE deductions matched what you actually owed. If they don't, HMRC usually sends a P800 tax calculation — a letter, by post, typically between June and November — telling you either that you're owed a refund or that you've underpaid.
- If you're owed money, the P800 will say whether you can claim online (the fastest way) or whether HMRC will send a cheque automatically if you don't claim within a set time.
- A Simple Assessment is a similar letter used when HMRC has worked out tax you owe (for example on a pension or savings) that can't be collected through your code.
- You don't need to file a Self Assessment return to get a P800 refund — it's a separate, simpler process.
A genuine P800 comes by post — never by text or email
HMRC will never tell you about a refund, or ask for your bank details, by text or email. If a "P800" or "tax refund" arrives as a text or email with a link, it's a scam — see below. Check any refund in your own HMRC account at gov.uk/personal-tax-account.
How to check and claim
You can check your code and claim a refund yourself, free, in a few minutes:
- Find your tax code — on a recent payslip, your P60 (end of year) or P45 (when you leave a job).
- Log in to your HMRC account — the Personal Tax Account or the HMRC app at gov.uk/personal-tax-account. There you can see your code, check your estimated tax, and see any refund due.
- Claim a P800 refund online — if your P800 or account says you can, choose a bank transfer and enter your details. HMRC says most online refunds arrive within about five working days. If you don't claim online in time, HMRC posts a cheque instead.
- Claim earlier years and missed relief — you can claim overpaid tax for the last four tax years, and claim tax relief for things like working-from-home, uniforms, tools and professional fees through gov.uk.
- Get a wrong code fixed — if a code is still wrong, tell HMRC so it doesn't keep happening (helpline below).
The 4-year clock
You can normally claim back overpaid Income Tax for four years from the end of the tax year. For example, tax overpaid in 2024/25 (year ended 5 April 2025) can be claimed until 5 April 2029. After that the year usually closes and the money is lost — so check sooner rather than later.
Do this right now
If you think you might be owed tax back, here's the calm, free order:
Check and claim — the safe way
- Check your code in the HMRC app. Open the official HMRC app or your Personal Tax Account at gov.uk/personal-tax-account. Look at your tax code and any refund shown.
- Claim online if you're owed. If a P800 or your account says you can claim, choose bank transfer — most refunds land in about five working days. You keep 100% of it.
- Never via a texted or emailed link. HMRC never sends a refund link by text or email. Only ever claim through gov.uk or the official HMRC app.
- Fix the code & go back 4 years. Ask HMRC to correct a wrong code on 0300 200 3300, and claim earlier years and any missed relief while you're there.
If you owe money instead, HMRC will tell you and usually collect it gradually through your code — don't panic.
For free, independent help: Low Incomes Tax Reform Group (LITRG) explains refunds in plain English, and Citizens Advice can help if your tax affairs are tangled. The HMRC Income Tax helpline is 0300 200 3300.
The two traps — scams and rebate firms
Trap 1 — "tax refund" texts & emails are scams
Fake HMRC refund texts and emails are one of the most common UK scams. They say you're owed money and push you to click a link "before you lose it" — the link steals your bank and personal details. HMRC never tells you about a refund, and never asks for bank or card details, by text or email. A real refund shows in your HMRC account or arrives by post.
Do this: don't click the link. Forward scam texts to 60599 and scam emails to phishing@hmrc.gov.uk, then delete them. Not sure if a message is real? Run it through Sorted's free scam check →
Trap 2 — rebate firms take a big cut of your money
"Tax rebate" or "tax refund" companies offer to claim for you, then take a commission — often around a third, and sometimes much more — out of money you could have claimed free yourself. HMRC does not "approve" or endorse any agent, whatever an advert says, and once you've signed up you may be tied in for future claims too.
If you're owed tax back, you keep every penny by claiming directly at gov.uk/claim-tax-refund. It's quick, free and the refund is all yours.