How to read a tax code
Most tax codes are a number followed by a letter. The number is your tax-free allowance divided by 10. So 1257L means you can earn about £12,570 in the tax year before paying income tax on that job — the standard Personal Allowance for 2025/26.
If your code number is higher or lower than 1257, HMRC has adjusted your allowance — for example adding a Marriage Allowance transfer, or taking off the value of a company car or untaxed income so it can be taxed through your wages.
You'll find your code on your payslip, your P60, in the HMRC app and in your Personal Tax Account. Our tax code checker decodes it for you.
What the letters mean
| Letter | What it means |
|---|---|
| L | You get the standard tax-free Personal Allowance |
| M | Marriage Allowance: you've received 10% of your partner's Personal Allowance |
| N | Marriage Allowance: you've 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 you've started a new job and your employer doesn't have the details they need |
| BR | All income from this job or pension is taxed at the basic rate (20%) |
| D0 | All income from this job or pension is taxed at the higher rate (40%) |
| D1 | All income from this job or pension is taxed at the additional rate (45%) |
| NT | You're not paying any tax on this income |
| K | You have untaxed income bigger than your allowance, so tax is collected on it through your pay |
S and C at the front
A code starting with S means Scottish income tax rates apply (for example S1257L). A code starting with C means Welsh rates apply. Scotland has extra codes such as SD0–SD3 for its different bands.
Useful tool
Type in your tax code and see what it means in plain English.
K codes
A K code works the other way round from a normal code. K475, for example, means about £4,750 is *added* to your taxable pay, because you have income or benefits worth more than your allowance — commonly a company car, medical insurance, or tax owed from an earlier year being collected.
There's a safety limit: tax collected through a K code shouldn't take more than half of your pay in any pay period.
Emergency codes: W1, M1 and X
If your code ends in W1, M1 or X, you're on an emergency code. Your tax is worked out on each week's or month's pay on its own, without looking at what you've earned and paid earlier in the year. It's common when you start a new job. Our emergency tax code guide explains how to get off it and claim back any overpayment.
If you have two jobs or a pension
You only get one Personal Allowance. It's normally given to your main job, so your second job or pension usually has a code like BR (taxed at 20%) or D0 (40%). That's expected — as long as your main job has the allowance.
If your second job earns more than your first, or your allowance is split between jobs, check the codes add up to the allowance you're due. You can ask HMRC to split your allowance between jobs.
What to do if your code is wrong
- Check your code in the HMRC app or your Personal Tax Account — you can see how it was worked out.
- Look for out-of-date information: a job you've left, a benefit you no longer get, or an estimate of income (like savings interest) that's wrong.
- Update your details online or contact HMRC. HMRC tells your employer the new code.
- Any overpaid tax is usually refunded through your pay automatically, or after the tax year ends by a P800 calculation.
Watch out for scams
HMRC won't ask for your bank details or password by text or email to change your code or pay a refund. Only use GOV.UK, the HMRC app or HMRC's published phone numbers.Going deeper on codes? Read our blog explainer: understanding your tax code.
Tax codes and Self Assessment
If you file a Self Assessment return, your tax code can be adjusted to collect small amounts you owe — under £3,000 — through your wages instead of a lump sum, if you file online on time. Equally, your code may include an estimate of untaxed income HMRC expects you to have. If you also file Self Assessment, TaxGo reads your P60 and other documents so your return matches what was already taxed through PAYE.