Your tax code: how to check it and how to get overpaid tax back

A tax code is the short string of numbers and letters your employer or pension provider uses to decide how much Income Tax to take off your pay. HMRC sets it, and you get one for each job or pension you hold. Get it wrong and you can overpay or underpay for years — and find out only by letter.

Where do you find your tax code?

Four places: the online check of your code for the current year on GOV.UK (you need an account), the HMRC app, your payslip, and a Tax Code Notice letter if HMRC sent one. Online and in the app you can also see codes for previous tax years and switch on paperless notifications, so HMRC emails you whenever the code changes.

ONLYWAY NEWSLIVEMarkets · 14.10ADOPT on-farm trial grant is open in England: apply by 2 DecemberMarkets · 14.10BridgeAI grants open on 21 October for UK AI SMEs: who can applyLife · 14.10England wants 10,000 new foster places: who can apply and what carers are paidTax · 14.10Your tax code: how to check it and how to get overpaid tax backJobs & Business · 14.10Minimum wage 2026: the rates, who is covered and how to get arrears backMoney · 13.10Money after a partner dies: what is paid and why the first three months decide itMoney · 13.10DWP posts 660,000 leaflets: pensioners reminded about £4,500 a yearMoney · 13.10Council tax: four legitimate ways to cut your billJobs & Business · 13.10DBS checks in England: the four levels, the £20 fee and the deadlines people missMoney · 13.10Attendance Allowance: £76.70 or £114.60 a week, and who can claimONLYWAY NEWS · appInstall the ONLYWAY NEWS appFresh UK news, classifieds, key dates and exchange rates on your home screen, one tap away. Free.NewsClassifiedsCalendarRates

What do the numbers mean?

They tell the employer or pension provider how much tax-free income you get from them that tax year. HMRC starts with your Personal Allowance and takes off income you have not paid tax on — untaxed interest or part-time earnings — plus deductions such as company benefits or the High Income Child Benefit Charge. The final digit is then replaced by a letter.

The commonest code is 1257L, used by most people with one job or one pension. GOV.UK's example: you have the standard £12,570 Personal Allowance, but your employer provides medical insurance worth £1,570. That company benefit cuts the tax-free amount to £11,000, so the code becomes 1100L.

What do the letters mean?

L means you get the standard Personal Allowance. 0T means it has been used up, or you have started a new job and your employer lacks the details to issue a proper code. BR means all income from that job or pension is taxed at the basic rate, which usually happens with a second job or pension. D0 and D1 put all that income at the higher and additional rate. NT means no tax is taken from that income at all. K means you have untaxed income greater than your Personal Allowance, and the code is worked out differently.

M and N concern Marriage Allowance: M means you received 10% of your partner's allowance, N that you transferred 10% of yours to them. An S at the start means Scottish rates, a C means Welsh rates, and C0T, CBR, CD0 and CD1 are the Welsh versions of those codes. GOV.UK has a "check what your tax code means" tool that decodes it, shows how much tax you will pay and says what to do next.

How do you tell if you are on an emergency code?

By the ending. The code ends in W1 if you are paid weekly (1257L W1), M1 if monthly (S875L M1), or X if your pay dates vary (C663L X). Your payslip may say NONCUM instead, depending on the payroll software. If it ends in none of those, it is not an emergency code.

ADV · A001ONLYWAY JEWELRY — gold, silver and platinumRings, chains, bracelets, earrings and pendants. Delivery across the UK.Advertise here

The difference matters. Normally tax is worked out on your total income so far in the tax year. On an emergency code it is worked out on that week's or month's pay alone, as if you were paid that amount every period of the year — which is how the wrong figure arises.

Why does a new job almost always start on one?

Because at your first payment the new employer tells HMRC you have started, but may not have your previous income and tax details. The cure is the P45 from your last job: hand it to the new employer and it takes you off the emergency code. If no P45 was issued, ask your previous employer for one.

HMRC then pulls the details together from both employers and sends the new code to you and your employer. That can take up to 35 days from your start date. If you have underpaid, you stay on the emergency code until the right tax for the year is paid; if you have overpaid, you are due a refund. If more than 35 days have passed and the code still looks wrong, there is a separate HMRC route for updating it.

How does a refund reach you?

Through the code. When HMRC updates it, they check whether they hold all your income details for the year. If they do, they work out the difference between the tax paid and the tax due and ask your employer or pension provider to refund it in your pay. Paid monthly, they should apply the new code on your next payment or the one after; paid weekly, on your third.

Until HMRC has those details — from an employer, pension provider or benefits office — no refund can happen. After the tax year ends HMRC collects them itself, checks the tax, writes to you if the amount is wrong, explains how to get a refund, and updates the code where needed. Refunds for anything other than a job or pension go through a separate GOV.UK route.

And if you have underpaid?

HMRC estimates what you owe when the code is updated and tries to collect it by adjusting the code, over one tax year or several. After the year ends they check again and write to you if the figure is off. Which is why the code is worth re-checking not once in a lifetime but every time you change jobs, take a second job, start getting company benefits, or begin drawing the State Pension.