UK Tax Codes Explained 2026: Every Code Decoded

UK tax codes explained 2026 — the sequence of letters and numbers on your payslip determines exactly how much income tax HMRC deducts from every pay packet. Most people never question their tax code, yet an incorrect code can leave you underpaying or overpaying by hundreds of pounds a year. This guide decodes every common UK tax code for 2026/27, explains how to check yours is correct, and shows you how to get a refund if HMRC has been taking too much.

What is a tax code?

A UK tax code tells your employer (or pension provider) how much of your income to pay you before deducting income tax. HMRC issues your code based on the information it holds about your income, benefits in kind, pension contributions and other allowances. Your employer applies it through the PAYE (Pay As You Earn) system and has no discretion over the amount deducted — they simply follow the code HMRC sends.

Your tax code appears on your payslip, your P60 (end-of-year tax certificate), your P45 (leaving a job), and in your personal tax account at gov.uk. Understanding it is one of the most valuable financial skills a UK employee can have in 2026.

The standard tax code: 1257L

The most common UK tax code in 2026/27 is 1257L. The number 1257 represents your tax-free Personal Allowance of £12,570 (divide by ten to get the allowance: 1257 × 10 = £12,570). The letter L means you are entitled to the standard tax-free Personal Allowance and nothing unusual applies to your tax situation.

If you earn up to £12,570 in the 2026/27 tax year, you will pay no income tax at all. Anything above that is taxed at the basic rate (20%) up to £50,270, the higher rate (40%) between £50,270 and £125,140, and the additional rate (45%) above £125,140. Note that the Personal Allowance is gradually withdrawn by £1 for every £2 earned above £100,000, so anyone earning over £125,140 has a personal allowance of zero.

What do the letters mean?

The letter at the end of your tax code is the key to understanding what adjustment HMRC has applied to your Personal Allowance.

L — Standard Personal Allowance

You are entitled to the standard Personal Allowance of £12,570. This is the default for the majority of UK employees in 2026/27.

M — Marriage Allowance received

Your spouse or civil partner has transferred 10% of their Personal Allowance to you via the Marriage Allowance scheme. This adds £1,257 to your allowance for 2026/27, saving you up to £251 in tax.

N — Marriage Allowance transferred

You have transferred 10% of your Personal Allowance to your spouse or civil partner. Your tax-free amount is therefore reduced by £1,257.

BR — Basic Rate on all income

All income from this source is taxed at 20% with no personal allowance applied. This is commonly used for a second job or a second pension where your Personal Allowance has already been allocated to your main income source. If you have a BR code on your main (highest-paying) job, this is almost certainly an error.

D0 — Higher Rate on all income

All income from this source is taxed at 40%. Like BR, this is typically used for a second income source when the employee is already a higher-rate taxpayer on their primary income.

D1 — Additional Rate on all income

All income from this source is taxed at 45%. Used for a third or subsequent income source for additional-rate taxpayers.

NT — No Tax

No tax is deducted from this income. Used in limited circumstances, such as for certain expenses payments, non-UK residents, or where HMRC has specifically authorised a nil deduction.

T — Other calculations required

A T code means HMRC needs to review your tax position — for example, if your income exceeds £100,000 and your Personal Allowance is being reduced. It can also be used at a taxpayer’s request for privacy.

0T — Zero allowance

You have no Personal Allowance, either because it has been used up or you are a new employee and HMRC has no starter information for you. All income is taxed according to the relevant rate band from the first pound.

K, W1, M1 and other prefix codes

K codes — negative allowance

A K code means you have a negative allowance — your deductions (such as unpaid tax from a previous year, or taxable benefits in kind like a company car) exceed your Personal Allowance. The number after K is divided by ten and added to your income for tax purposes. For example, K500 means £5,000 is added to your taxable income. There is a statutory cap: your employer cannot deduct more than 50% of your pre-tax pay in a single pay period under a K code.

W1 and M1 — Week 1 / Month 1 basis

The suffix W1 (weekly pay) or M1 (monthly pay) after a tax code means you are being taxed on a non-cumulative basis — each pay period is treated as if it were the first of the tax year rather than a running total. This is often applied when you start a new job and your P45 is delayed, or at the start of the tax year as a temporary measure. Being on a W1/M1 code can mean you overpay tax early in the year, because the cumulative underpayment correction mechanism is not applied. Contact HMRC to have it removed once your records are updated.

X codes

X after a tax code serves a similar purpose to W1/M1 for irregular pay periods, such as casual or zero-hours employment.

Emergency tax codes

If your employer does not have a P45 from your previous job and you have not completed a starter checklist, HMRC may place you on an emergency tax code. In 2026/27 the emergency code is typically 1257L W1 or 1257L M1. This taxes each pay period in isolation, which often results in over-taxation if your income is uneven across the year.

Emergency tax is not automatically refunded unless HMRC processes your correct code and recalculates the year’s liability. If you have been on an emergency code for more than a month or two, contact HMRC via your Personal Tax Account or call 0300 200 3300 to get the correct code issued.

Scottish and Welsh tax codes

If you live in Scotland, your tax code is prefixed with S (e.g. S1257L). Scottish income tax rates differ from the rest of the UK in 2026/27 and are set by the Scottish Parliament. Scotland has a starter rate of 19%, a basic rate of 20%, an intermediate rate of 21%, a higher rate of 42%, and an advanced rate of 45% for income between £75,000 and £125,140, with a top rate of 48% above £125,140.

If you live in Wales, your code is prefixed with C (e.g. C1257L). Welsh income tax rates currently mirror the rest of England and Northern Ireland, but the Welsh Government has powers to vary them.

Residency for tax purposes is based on where you live, not where you work. If you live in Scotland but work in England, you should have an S-prefix code.

How to check your tax code

The quickest way to check your current tax code in 2026 is to log in to your HMRC Personal Tax Account at gov.uk/personal-tax-account. You can also see your code on your most recent payslip, your P60 from the previous April, or any letter from HMRC about a code change (a P6 or P9 notice).

To verify your code is correct, work out what your total expected income for the year is across all sources (salary, second job, rental income, state pension, benefits in kind) and compare it against what HMRC appears to be taxing. If the number in your code does not match £12,570 divided by ten (i.e., 1257) and you have no unusual circumstances, investigate further.

What to do if your tax code is wrong

You can update HMRC online via your Personal Tax Account, or by calling the HMRC income tax helpline on 0300 200 3300 (Monday to Friday, 8am to 6pm). Have your National Insurance number and payslip to hand. HMRC will issue a new P6 or P9 notice to your employer within a few weeks, and the correction will typically be applied in your next pay run.

You do not need to wait for HMRC to take action — if you believe your code is wrong, you have the right to challenge it. The most common reasons for incorrect codes include: not notifying HMRC when you stop receiving a benefit in kind; having two jobs where the Personal Allowance is split incorrectly; and underpaid tax from a previous year being collected over too short a period.

Claiming a tax refund

If you have overpaid tax in the current year, HMRC will usually correct it automatically through your PAYE code and issue a P800 tax calculation letter after the end of the tax year (April). If you have overpaid in previous years, you can claim back up to four years via your Personal Tax Account or by submitting a self-assessment return. For most employed taxpayers, HMRC processes refunds within six to twelve weeks of receiving the claim.

Frequently Asked Questions

What does the tax code 1257L mean in 2026?

1257L is the standard UK tax code for 2026/27. The number 1257 represents a Personal Allowance of £12,570 (1257 × 10), which is the amount you can earn tax-free. The letter L indicates you are entitled to the standard Personal Allowance with no special adjustments.

Why do I have a BR tax code on my second job?

A BR code means all income from that source is taxed at the basic rate of 20% with no Personal Allowance. This is correct if your Personal Allowance has already been allocated to your main job. If BR is appearing on your main (highest-paying) job, it is likely an error and you should contact HMRC immediately.

How do I know if I am on an emergency tax code?

Emergency tax codes in 2026/27 typically appear as 1257L W1 or 1257L M1 on your payslip. The W1 or M1 suffix means you are being taxed on a week-by-week or month-by-month basis rather than cumulatively, which can result in overpayment. Contact HMRC to have your correct code issued.

Can I be taxed too much with a K tax code?

K codes increase the amount of income subject to tax, but there is a statutory protection: your employer cannot deduct more than 50% of your gross pay in any single pay period under a K code, regardless of how large the K number is. Any uncollected tax is carried forward to future pay periods.

Understanding your tax code is one step towards making the most of your UK earnings. To see how tax affects take-home pay across different roles and salaries, browse live vacancies at UK Jobs Alert. You may also find our guides to accounting and finance careers and NHS pharmacist salaries useful for salary benchmarking.