How to check your tax code and what the letters mean in 2026/27
Published · 4 min read · Figures checked . UK rules and rates change, so check the official sources below before you act.
Your tax code tells your employer or pension provider how much Income Tax to take from your pay. This guide explains where to find your code, how to read the number and letters, and how it can be corrected.
What a tax code is
HMRC gives your employer or pension provider a tax code so they can work out how much Income Tax to deduct. You get one code for each job or pension. If the tax taken looks wrong, the code may be the reason.
You can find your code in your online HMRC account or the HMRC app, on your payslip, or on a Tax Code Notice letter from HMRC. The online service also shows codes from earlier tax years, and you can sign up for paperless notifications so HMRC emails you when a code changes.
How to read the number
The number shows the tax-free amount you get through that job or pension in the year. HMRC starts with the standard Personal Allowance and takes away things like untaxed income and some company benefits. The last digit is then swapped for a letter. GOV.UK gives an example: a medical insurance benefit of £1,570 lowers the allowance to £11,000, giving the code 1100L.
What the letters mean
- L: you get the standard Personal Allowance.
- M: you have received 10% of your partner's Personal Allowance through Marriage Allowance.
- N: you have transferred 10% of your Personal Allowance to your partner through Marriage Allowance.
- T: other calculations are included in working out your Personal Allowance.
- 0T: your Personal Allowance has been used up, or a new employer does not yet have the details needed to issue a code.
- BR, D0 and D1: all income from that job or pension is taxed at the basic, higher or additional rate. This is usually used when someone has more than one job or pension.
- K: you have untaxed income that is more than your Personal Allowance, so the calculation works differently.
- NT: no tax is taken from that income.
Scotland and Wales
A code starting with S means your income is taxed using Scottish rates. A code starting with C means it is taxed using Welsh rates. Income Tax bands differ for Scottish taxpayers, so the same income can lead to a different tax bill in Scotland. The current rates are on the GOV.UK Income Tax rates page linked below.
Emergency tax codes
A code ending in W1, M1 or X, or sometimes NONCUM on a payslip, is an emergency code. Tax is worked out on only that week's or month's pay, as if you earned the same amount every period of the year, so the amount can be wrong. It often happens when a new employer lacks your earlier pay and tax details. Giving your new employer a P45 from your last job can help. HMRC usually updates the code within 35 days of starting a job. If you have paid too much tax, you can claim a refund.
Why a code can change
According to GOV.UK, HMRC may change a code when you start a new job, get taxable state benefits, start another job or pension, earn savings interest above your Personal Savings Allowance, or claim Marriage Allowance or tax relief on work expenses. A change in your State Pension or in company benefits reported by your employer can also change it.
If you think your code is wrong
The quickest route is the Check your Income Tax service on GOV.UK. It lets you view your code and Personal Allowance, see estimated earnings and expected tax, and update job or pension details. HMRC says it then updates your code and tells you and your employer within 15 working days. Monthly-paid people should see the new code on the next or following payslip; weekly-paid people on the third payslip. If you cannot use the online service, you can contact HMRC by phone or online enquiry. The service cannot be used if Self Assessment is your only way of paying Income Tax.
This guide is general information. It applies to people paying Income Tax through PAYE on jobs or pensions, and is less relevant if you only pay through Self Assessment.
Check before you act
Rules, rates and HMRC processes can change, so confirm the details on the official pages linked below before you rely on them.
Sources
For information only. See our disclaimer and editorial standards. Spotted an error? Tell us.
