UK Tax Codes Explained (2026/27): 1257L, BR, K and Emergency Codes

What a UK tax code actually is

Your tax code is a short string of numbers and a letter — like 1257L — that tells your employer's payroll how much tax-free income to give you before Income Tax is deducted under PAYE. Get it right and your take-home pay matches the rules exactly; get it wrong and you can overpay or underpay by hundreds of pounds a year. You can sanity-check yours in seconds with our tax code calculator.

The number is your tax-free allowance divided by ten. 1257L means £12,570 of tax-free pay — the standard Personal Allowance for 2026/27 — spread evenly across the year. Everything above that is taxed at the Income Tax band rates, while National Insurance is calculated separately and is not affected by your tax code at all.

HMRC issues the code, not your employer. When something changes — a second job, a company car, a backdated refund, or claiming Marriage Allowance — HMRC updates the code and sends a new one to payroll, usually via a coding notice (form P2) you can also see in your Personal Tax Account.

The most common code: 1257L

Around three in four UK employees are on 1257L, the default for someone with one job, the full Personal Allowance and no adjustments. If that describes you, your first £12,570 is tax-free and the rest is taxed at 20% up to £50,270 — exactly the maths our PAYE take-home calculator and our full take-home pay walkthrough run through step by step.

The letter L simply means you get the standard tax-free allowance. Other suffixes tweak the same idea: M means you've received 10% of a partner's allowance through Marriage Allowance; N means you've given yours away; T flags a code with other calculations HMRC wants to review annually.

BR, D0 and D1 — codes for a second income

If you have more than one job or a pension alongside work, your main income usually keeps 1257L and your second income gets a flat-rate code so you don't use the allowance twice. BR taxes every pound at the 20% basic rate, D0 at 40% (higher rate) and D1 at 45% (additional rate). Model how a second job stacks on top of your salary with the take-home pay calculator.

BR is correct when your first job already uses the full Personal Allowance — for example a £30,000 main job plus weekend shifts. But if your main job pays less than £12,570, a BR code on the second job wastes part of your allowance, and you can ask HMRC to split it. Higher earners crossing £50,270 in total should expect Income Tax at 40% on the top slice, which a D0 second-job code applies automatically.

Emergency tax: W1, M1 and X

An emergency code — shown as 1257L W1, 1257L M1 or 1257L X — gives you the tax-free allowance but only for the current pay period, ignoring what you've earned so far this year. New arrivals to the UK and anyone starting a job without a P45 very often land on it, which is why our Brazilian readers ask about it more than any other code. Check the damage against your salary with the tax code calculator or the income tax calculator.

Emergency codes are not a penalty and they don't always overtax you, but because they ignore your year-to-date figures they frequently do. The fix is usually automatic: once HMRC receives your first Full Payment Submission and any P45, it issues a cumulative 1257L and payroll refunds the overpaid tax in your next payslip. If it hasn't sorted itself within two pay cycles, call HMRC or update your details in the Personal Tax Account.

K codes — when deductions exceed your allowance

A K code is the one that surprises people, because it works backwards. Instead of tax-free income, it means your untaxed income or benefits (a company car, unpaid tax from a previous year, or the State Pension) are larger than your Personal Allowance, so the code adds that excess to your taxable pay. K475 adds £4,750 to what you're taxed on rather than removing it.

K codes are common for higher earners with a company car or those repaying an old tax bill through their code. The law caps the extra tax at 50% of your pre-tax pay in any period, so a K code can never take more than half your wage. If a K code appears unexpectedly, it usually points to a benefit-in-kind or an underpayment you can query — and if a big benefit like a car is involved, our salary sacrifice guide explains how some are handled tax-efficiently instead.

Special codes: NT, 0T and Scottish/Welsh prefixes

A few codes sit outside the usual pattern. NT means No Tax — used for some non-residents or specific pension situations. 0T gives no allowance and taxes everything from the first pound (common when you start a job with no P45 and haven't completed a starter checklist). A leading S (as in S1257L) means Scottish rates apply, and C means Welsh rates — the National Insurance charge is identical UK-wide, but Scottish Income Tax bands differ enough to change your monthly take-home pay noticeably.

Where you're tax-resident, not where your employer is based, decides the S or C prefix. If you moved between nations mid-year, check the prefix is right — a Scottish worker wrongly on rUK rates (or vice versa) can be out by more than £100 a month, as our worked examples on the higher salary bands like £55,000 and £70,000 show.

How to check — and fix — a wrong tax code

The fastest check is to compare your payslip's net pay against an independent calculation. Enter your salary and code into the tax code calculator, then cross-check the deductions with the income tax and National Insurance calculators. A mismatch of more than a few pounds usually means the code is wrong or out of date.

Five steps to correct an error

• Find the code on your payslip (top corner) or in your HMRC Personal Tax Account app.
• Verify the allowance — divide the number by 10; 1257 = £12,570. Anything lower means a reduction you should understand.
• Check for stale benefits — an old company car or expenses claim can leave a reduced code long after it ended.
• Contact HMRC via the app, online, or 0300 200 3300; they reissue the code to your employer within days.
• Reclaim overpaid tax — refunds usually arrive automatically in your next payslip once the cumulative code is applied, or via a P800 after year end.

Tax codes across different salaries

The right code (1257L) produces the same effective result at every salary, but the amount at stake from getting it wrong grows with income. On a modest wage an emergency code might cost you £20–£40 a month; for a higher earner near the £45,000 or £70,000 mark, a missing allowance or a stray BR/D0 code can distort a payslip by well over £100. Whatever you earn, our salary-specific pages — from £36,000 through £45,000, £55,000 and £70,000 — show the correct deductions for a standard 1257L code so you have a benchmark to compare against.

If you also repay a student loan, remember it is deducted separately from your tax code — our student loan calculator and the Plan 2 repayment guide cover the thresholds. And if you pay into a workplace pension, a salary sacrifice arrangement changes your taxable pay before the code is even applied.