UK Tax Code Explainer — 1257L, BR, D0, D1, K, NT and More
Understand what your UK tax code means. Guide to 1257L (standard Personal Allowance), BR (basic rate), D0 (higher), D1 (additional), K codes (negative allowance), NT (no tax), M/N suffix (Marriage Allowance), emergency codes, and how to fix a wrong code.
Last updated · Tax year 2026/27
Common UK tax codes
| Code | Meaning | Explanation |
|---|---|---|
| 1257L | Standard Personal Allowance | Your employer gives you the full £12,570 Personal Allowance before deducting Income Tax. The vast majority of UK employees have this code. |
| BR | Basic Rate — all income at 20% | No Personal Allowance — all income from this job is taxed at 20%. Common on second jobs when your main job already uses your PA. |
| D0 | All at higher rate (40%) | Applied when HMRC knows your total income already sits in the higher-rate band, so every £ from this job is taxed at 40%. |
| D1 | All at additional rate (45%) | Same concept as D0, but for income expected to fall entirely within the additional-rate band (above £125,140). |
| K XXXX | Negative allowance | When deductions (untaxed benefits, state pension above PA, tax owed from previous years) exceed your PA. The 'XXXX' × 10 is added to your taxable income. |
| NT | No Tax | Unusual — applied during specific scenarios like statutory sick pay or certain non-resident cases. Check with HMRC if you see this unexpectedly. |
| 1257L + M | Received Marriage Allowance | Your spouse transferred £1,260 of their PA to you. Your effective PA becomes £13,830. Code shows as 1383M. |
| 1257L + N | Transferred Marriage Allowance | You transferred £1,260 of your PA to your spouse. Your effective PA drops to £11,310. Code shows as 1131N. |
| W1 / M1 / X (suffix) | Emergency / non-cumulative | Applied when HMRC lacks full year-to-date pay info. Each pay period is taxed in isolation. Usually replaced once your P45 or Starter Checklist is processed. |
How tax codes work
Your tax code tells your employer (or pension provider) how much tax-free allowance to apply before deducting Income Tax from your pay. The number is your Personal Allowance divided by 10, plus or minus various adjustments.
HMRC sets your code at the start of each tax year, updating it when your circumstances change — new employer, new benefits, claimed Marriage Allowance, or an under/overpayment from a previous year.
What to do if your code looks wrong
- Check your latest payslip for the current code.
- Log in to your Personal Tax Account at gov.uk/personal-tax-account to see HMRC's breakdown.
- If your tax code seems wrong, call HMRC on 0300 200 3300 or update details online.
- Over-paid tax within the year is usually refunded automatically via subsequent PAYE.
- Under-paid tax is often collected by adjusting the following year's code.
Related tools
- Salary calculator — see how your tax code affects take-home.
- Two-jobs calculator — common use-case for BR/D0 codes.
- Methodology — all sources + testing approach.
Frequently asked questions
- What does tax code 1257L mean?
- 1257L is the standard UK tax code for 2026/27 — "1257" represents your Personal Allowance (£12,570) divided by 10, and "L" means you get the standard allowance. Unchanged because the PA is frozen until April 2028.
- What is BR tax code?
- BR means Basic Rate — all income from this job is taxed at 20% with no Personal Allowance. Common for second jobs when the PA is already assigned to your main employment.
- What are D0 and D1 codes?
- D0 = all at higher rate (40%). D1 = all at additional rate (45%). Typically applied to second jobs or pensions when you are already a higher / additional rate taxpayer.
- What is a K tax code?
- A K code means your deductions (e.g. untaxed benefits, tax owed from previous years) exceed your Personal Allowance. The number after K is the 'negative allowance' — HMRC adds that amount to your taxable income.
- What is NT?
- NT = No Tax. Applied in rare cases like statutory sick pay during sickness certification, or certain non-residents. If you have NT and think it's wrong, contact HMRC — you may owe a lot at tax-year-end.
- How do I fix a wrong tax code?
- Log into your Personal Tax Account at gov.uk/personal-tax-account, or call HMRC on 0300 200 3300. Over-paid tax is usually refunded via PAYE in subsequent months; under-paid tax may be collected in next year's code.
- What's an emergency tax code?
- Codes ending in W1 (week 1), M1 (month 1), or X — HMRC uses these when it lacks enough info. They tax only the current period in isolation, ignoring year-to-date earnings. Usually replaced once HMRC has your P45 or Starter Checklist.