Your tax code is the short mix of numbers and letters printed on your payslip, usually something like 1257L. It tells your employer or pension provider how much tax-free pay you get and how much Income Tax to take each payday. If it is wrong, you can pay too much tax for months without noticing, or end up with a bill later.
This guide is for anyone working in the UK who wants to understand their payslip, especially if you have just arrived, started a new job, taken on a second job or seen your tax jump for no clear reason. It covers the 2026 to 2027 tax year (6 April 2026 to 5 April 2027).
What is a tax code?
HM Revenue and Customs (HMRC) gives your employer or pension provider a tax code for you. Payroll software uses it to work out how much Income Tax to deduct from your pay. You get a separate tax code for each job or pension, so someone with two jobs will have two codes.
You can find your tax code on your payslip, in the HMRC app, in your personal tax account online, or on a “Tax Code Notice” letter from HMRC.
What the numbers mean
The numbers show how much tax-free income you get from that job or pension in the tax year, with the last digit removed. The most common code for people with one job or pension is 1257L. That matches the standard Personal Allowance of £12,570 for 2026 to 2027.
So 1257L means: “this person can earn £12,570 from this job tax-free this year, and the standard allowance applies”. A lower number usually means HMRC is taking something off your allowance, such as a company car or untaxed income. A higher number can mean you have tax relief added, for example for work expenses or Marriage Allowance.
Bear in mind that the Personal Allowance goes down by £1 for every £2 of adjusted net income above £100,000, and is nil at £125,140, so high earners will see smaller numbers or a different code.
What the letters mean
The letters tell payroll about your situation and how to treat the allowance. These are the ones you are most likely to see:
| Letter or code | What it means |
|---|---|
| L | You get the standard tax-free Personal Allowance |
| M | You have received 10% of your partner’s Personal Allowance (Marriage Allowance) |
| N | You have transferred 10% of your Personal Allowance to your partner |
| T | Your code includes other calculations to work out your allowance |
| 0T | Your allowance has been used up, or your new employer does not have your details |
| BR | All income from this job or pension is taxed at the basic rate (often a second job) |
| D0 | All income from this job or pension is taxed at the higher rate |
| D1 | All income from this job or pension is taxed at the additional rate |
| NT | No tax is taken from this income |
| K | You have untaxed income or benefits bigger than your allowance, so tax is collected through this job |
S and C: Scotland and Wales
A code starting with S (for example S1257L) means your income is taxed using Scottish rates. A C (for example C1257L) means Welsh rates. Scotland has its own bands, so take-home pay can be noticeably different. You can compare take-home pay in Scotland and the rest of the UK with our free calculator.
K codes
A K code is not a mistake in itself. It means things like company benefits or untaxed income add up to more than your allowance, so extra tax is collected through your wages. There is a safety limit: an employer or pension provider cannot take more than half of your pre-tax pay or pension when using a K code.
Emergency tax codes: W1, M1 and X
If you see W1, M1 or X after your code (for example 1257L M1), you are on an emergency tax code. W1 is used if you are paid weekly, M1 if you are paid monthly, and X if your pay dates vary. Some payroll software shows “NONCUM” instead.
Emergency codes work out your tax as if you earn the same amount every week or month. They ignore what you have already earned and paid earlier in the tax year, so the amount taken may be wrong. This is very common when you start your first job in the UK, change jobs mid-year without a P45, or start a pension.
Give your P45 from your last job to your new employer. HMRC usually updates your code within 35 days. If it has been more than 35 days and you are still on an emergency code, update your details online or contact HMRC.
How to check your tax code: step by step
- Find your code on your latest payslip, or sign in to the HMRC app or your personal tax account.
- Check that the employment or pension listed is correct and that HMRC has the right estimated income for the year.
- Check any company benefits (such as a company car or medical insurance) and expenses shown.
- Look for letters you do not expect, such as 0T, BR on your main job, or W1/M1 that has been there for months.
- If something is wrong or missing, update it in the online “Check your Income Tax” service, then claim any tax relief on work expenses you are owed.
- HMRC will tell you and your employer the new code within 15 working days.
- Once the new code is on your payslip, check your take-home pay with our free calculator to see if the deductions now look right.
Why your tax code might change
HMRC changes your code whenever you need to pay a different amount of tax. Common reasons include:
- starting a new job, or taking on a second job or pension
- getting company benefits, such as a company car
- savings interest above your Personal Savings Allowance
- taxable state benefits or changes to your State Pension
- claiming Marriage Allowance or tax relief on work expenses
- having underpaid or overpaid tax in an earlier year
Common mistakes
- Ignoring an emergency code. If W1 or M1 is still on your payslip after a couple of months, act on it rather than waiting for the end of the tax year.
- Putting your allowance on the wrong job. With two jobs, your main job should normally get the allowance (for example 1257L) and the second job BR. If it is the other way round, ask HMRC to swap them.
- Not handing over your P45. Without it, your new employer may have to use 0T or an emergency code.
- Assuming HMRC is always right. GOV.UK says it is your responsibility to check you are paying the right amount of tax.
- Forgetting old benefits. If you hand back a company car and HMRC is not told, your code may keep reducing your allowance.
FAQ
Is 1257L the right code for me?
It is the right code for most people with one job or pension and no other adjustments in 2026 to 2027. If you have benefits, a second income, Marriage Allowance or work expenses, a different code may be correct.
Will I get money back if I paid too much tax?
Usually yes. HMRC can ask your employer or pension provider to refund the difference through your pay, normally once the new code is applied. HMRC needs your income details before it can refund you.
What happens if I paid too little?
HMRC estimates what you owe and may collect it by adjusting your tax code, sometimes over more than one tax year. It checks your tax again after the year ends.
I have two jobs. Why is one taxed at BR?
Your Personal Allowance is normally used against your main job, so all pay from the second job is taxed at the basic rate. This is expected, not an error, as long as your main job has the allowance.
Next steps
Once you know your tax code, the best check is to compare your payslip with an estimate. Use our free UK take-home pay calculator to see your expected Income Tax, National Insurance and net pay. For other money, visa and housing checks, see our Free UK Checks, and for the official rules read Tax codes on GOV.UK.
This guide is general information, not legal, immigration or financial advice. Check GOV.UK for your situation.
