What does my UK tax code mean?
TL;DR
UK tax codes combine a number (your tax-free allowance ÷ 10) with a letter that tells employers how to deduct income tax. For 2026/27, 1257L appears to remain the standard code reflecting the £12,570 personal allowance, while letters like BR, 0T, D0, D1, K, S, C and NT signal special situations.
In one sentence
A UK tax code is HMRC's instruction to your employer that combines a number representing your tax-free allowance with a letter explaining how that allowance is applied.
In plain English
Your tax code is issued by HMRC and tells your employer (or pension provider) how much income tax to deduct under PAYE. Most codes have two parts: a number that, multiplied by ten, gives your annual tax-free allowance, and a letter describing adjustments. Based on HMRC guidance for 2026/27, the personal allowance remains £12,570 for most people, which is why 1257L appears as the most common code.
The letter matters as much as the number. An L means you get the standard personal allowance; an M or N indicates you have given or received the Marriage Allowance; a Kprefix means deductions exceed your allowance and are added to your taxable pay. Letters such as S and C denote Scottish and Welsh taxpayers respectively.
Some codes - BR, 0T, D0, D1 and NT - do not give a personal allowance at all. These appear most often on second jobs, when HMRC lacks information, or in specific contractual situations. A non-cumulative marker (W1, M1 or X) tells the employer to tax each period in isolation, which is consistent with emergency tax behaviour.
Tax codes change during the year as HMRC updates them - for new benefits, changes in income, underpayments collected through PAYE, or relief claims. The code on your latest payslip should match the most recent code notice (P2) HMRC sent you. If they differ, that may indicate a delay in your employer applying the new code rather than an error.
Every common UK tax code, in one table
| Code | What it indicates | Typical scenario |
|---|---|---|
| 1257L | Standard £12,570 allowance | One job, no adjustments |
| BR | All income taxed at 20% | Second job where allowance is used elsewhere |
| 0T | No personal allowance; bands applied | New starter without P45, allowance exhausted |
| D0 | All income taxed at 40% | Second job at higher-rate level |
| D1 | All income taxed at 45% | Second job at additional-rate level |
| K (prefix) | Negative allowance - deductions exceed allowance | Untaxed income, owed tax, large benefits-in-kind |
| M | Received Marriage Allowance from spouse | Couple where one transfers 10% of allowance |
| N | Transferred Marriage Allowance to spouse | The giver in a Marriage Allowance claim |
| T | Other calculations apply (e.g. tapered allowance) | Income near £100,000 where allowance tapers |
| NT | No tax to be deducted | Specific overseas or insolvency cases |
| S (prefix) | Scottish income tax rates apply | Main home in Scotland |
| C (prefix) | Welsh income tax rates apply | Main home in Wales |
| W1 / M1 / X | Non-cumulative (emergency) basis | New job without full P45 details |
Worked example (2026/27 figures)
Suppose Alex earns £36,000 with code 1257L on a cumulative basis. The £12,570 allowance leaves £23,430 of taxable pay, all within the basic-rate band (up to £50,270). Income tax for the year would be £23,430 × 20% = £4,686, or roughly £390.50 per month. National Insurance at 8% on earnings between £12,570 and £50,270 adds approximately £1,874 per year. These figures are based on the HMRC thresholds listed for 2026/27.
If Alex picked up a second job earning £8,000 a year, HMRC would typically apply BR to that job - taxing all £8,000 at 20% (£1,600), since the personal allowance is already used at the main job. This does not prove an error; it appears consistent with how PAYE allocates allowances across multiple sources.
Common mistakes people make
- Assuming BR on a second job is always wrong - it is often correct.
- Believing a K code is a penalty - it simply collects an offset through PAYE.
- Thinking 1257L automatically applies - if HMRC lacks data, 0T or emergency codes may appear.
- Ignoring the W1/M1/X marker - non-cumulative tax can over- or under-collect during the year.
- Confusing the S and C prefixes with errors - they reflect devolved tax residency.
When this might apply to you
- You started a new job and your employer used a starter declaration before HMRC issued a code.
- You took on a second job or pension on top of an existing income source.
- You receive taxable benefits in kind, such as a company car or private medical insurance.
- You moved your main home into or out of Scotland or Wales.
- You claimed or transferred Marriage Allowance.
What to do if your code looks wrong
- Check your latest P2 coding notice in your HMRC Personal Tax Account.
- Compare the code shown there to the code on your most recent payslip.
- Use our /check tool to compare gross-to-net based on the figures provided.
- If the codes differ, ask your payroll team when the new code will be applied.
- If the HMRC code itself looks wrong, update your details in your Personal Tax Account or call HMRC.
When to contact HMRC, payroll, or a professional
Contact payroll first if the code on your payslip differs from your latest HMRC notice. Contact HMRC if the underlying code seems to reflect outdated information about your income, benefits, or residency. Consider a tax adviser if you have multiple income sources, untaxed income, or income near the £100,000 personal allowance taper, where a T code may be appropriate.
Frequently asked questions
What is the standard UK tax code for 2026/27?
Based on HMRC guidance, 1257L appears to remain the standard code for most employees with one job and the full personal allowance of £12,570.
Does the letter at the end of my tax code matter?
Yes - letters such as L, M, N, T, K, BR, D0, D1, NT, S and C indicate how the personal allowance is applied or where tax is collected differently.
Why does my tax code start with K?
A K-prefix code may indicate that deductions (for example untaxed income or owed tax) are larger than your personal allowance, so additional tax is collected through your salary.
What does the W1, M1 or X marker mean?
These markers signal a non-cumulative (emergency) basis, meaning tax is calculated on each pay period in isolation rather than across the full year.
Is BR always wrong on a second job?
Not necessarily - BR is commonly used for second jobs where the personal allowance is already used elsewhere, but it is worth reviewing if your circumstances changed.
Who issues my tax code?
HMRC issues tax codes to employers and pension providers; the employer applies whatever code HMRC has provided on the latest tax code notice.
How do I change my tax code if it looks wrong?
You can contact HMRC via your Personal Tax Account or by phone; HMRC will issue an updated code to your employer if a change is appropriate.
Related guides and tools
- Emergency tax explained
- Wrong tax code checklist
- PAYE: cumulative vs non-cumulative
- Scottish vs rest-of-UK income tax
- Tax code checker tool
- Take-home pay calculator
- Run a free payslip check
This page is educational and does not constitute regulated tax advice. Figures cited reflect HMRC publications for 2026/27 at the date of last verification.