What Does Your Tax Code Mean? UK Tax Codes Explained 2026/27

Your payslip has a tax code on it. Most people glance at it and move on. But your tax code controls exactly how much income tax gets taken from your pay — and if it’s wrong, you could be overpaying or underpaying tax without realising it.

This guide explains every part of your tax code — what the numbers and letters mean, what common codes like BR and K actually do to your pay, and how to check yours is correct.

What is a tax code?

Your tax code is a short combination of numbers and letters that tells your employer how much income tax to deduct from your pay each month. It is set by HMRC and applied through the PAYE system. Most employees have a single tax code, but if you have multiple jobs you’ll have a separate code for each.

Your tax code appears on every payslip, on your P60 at year end, on your P45 when you leave a job, and in any correspondence from HMRC. You can also see it in your HMRC Personal Tax Account at gov.uk.

The most common tax code — 1257L explained

For most employees in England, Wales, and Northern Ireland in 2026/27, the tax code is 1257L. Here’s how to read it:

So 1257L means: you have a tax-free allowance of £12,570 for this tax year. Everything you earn above that is taxable at the appropriate rate.

What if your number is different?

If your code shows a lower number than 1257, your personal allowance has been reduced. Common reasons include:

• Underpaid tax from a previous year being recovered gradually
• Untaxed income from another source (rental income, savings interest)
• A company car or other taxable benefit in kind
• State pension payments that exceed your allowance

If your code shows a higher number than 1257, your allowance has been increased. The most common reason is marriage allowance — where a lower-earning spouse transfers 10% of their personal allowance to their partner, pushing the recipient’s code up to 1383M.

What the letter means — every code explained

Emergency tax codes

If you start a new job without providing a P45 or completing a starter checklist, your employer may have to use an emergency tax code. Emergency codes are usually 1257L W1, 1257L M1, or 1257L X.

The W1 (week 1) and M1 (month 1) suffixes mean your tax is calculated on a non-cumulative basis — each pay period is treated independently rather than cumulatively across the year. This can lead to overpaying tax if your earnings vary month to month. Once HMRC has your full details, the code will be updated to a standard cumulative code.

K codes explained

A K code works in reverse to a normal tax code. Instead of reducing your taxable income by a personal allowance, a K code adds an amount to your taxable income.

For example, K500 means that £5,000 is added to your gross income before tax is calculated. This effectively means you’re paying tax on more than you actually earn from this employment. K codes are most common for employees with high-value company cars, or where underpaid tax is being recovered and the adjustment exceeds the personal allowance.

There is a legal safeguard: the amount deducted due to a K code cannot exceed 50% of your gross pay in any single pay period.

Tax codes in Scotland

If you live in Scotland, your tax code will start with S — for example S1257L. Scottish Income Tax has more bands than the rest of the UK, with rates starting at 19% for the starter rate. The salary calculator covers Scottish rates — just select Scotland and it switches automatically.

How to check your tax code is correct

The most important question is: does the number in your code match your expected personal allowance? For most employees in 2026/27 it should be 1257.

If it’s lower, find out why. If you don’t recognise the reason, contact HMRC. The most common causes of incorrect codes are:

• Old company car benefits that are no longer active
• Underpaid tax from previous years that has already been repaid
• Incorrect earnings information held by HMRC
• A previous employer failing to report the correct leaving date

Use the free OS Payroll salary calculator to enter your exact tax code and see what it means for your take-home pay. If your code has been reduced, you can model how much extra tax you’re paying.

→ Try the free salary calculator

What to do if your tax code is wrong

Contact HMRC as soon as possible. You can:

• Update it online via your Personal Tax Account at gov.uk
• Use the check your income tax service at gov.uk/check-income-tax
• Call HMRC on 0300 200 3300 (Mon–Fri, 8am–6pm)

HMRC will issue an updated code directly to your employer. If you’ve been overpaying tax, a rebate will follow — usually as an adjustment through your payslips over the remainder of the tax year, or as a direct refund at year end.

Frequently asked questions

What does 1257L mean on my payslip?

1257L means you have the standard personal allowance of £12,570 for 2026/27. The L indicates you’re entitled to the basic personal allowance. All income above £12,570 is taxable.

Why is my tax code not 1257L?

Your code may be different because of a company benefit, underpaid tax from a previous year, untaxed income from another source, or marriage allowance. Check your HMRC Personal Tax Account to see the breakdown.

What does BR mean on my payslip?

BR means all income from that job is taxed at the basic rate (20%) with no personal allowance applied. It’s commonly used for second jobs. If BR appears on your main job, contact HMRC — you’re likely paying too much tax.

What is an emergency tax code?

Emergency codes (1257L W1 or 1257L M1) are applied when HMRC doesn’t have enough information about your earnings. They calculate tax on a week-by-week or month-by-month basis rather than cumulatively, which can mean overpaying. They should be updated once your employer receives your full tax details.

How do I find my tax code?

It’s on every payslip, your P60, your P45, and in your HMRC Personal Tax Account at gov.uk. You can also call HMRC on 0300 200 3300.

Can I change my tax code?

You can’t change it directly, but you can ask HMRC to update it if it’s wrong. Contact them via your Personal Tax Account online or by phone. They’ll issue a new code to your employer.

What does the S prefix mean?

S before your tax code — for example S1257L — means you’re a Scottish taxpayer and pay Scottish Income Tax rates, which have more bands than the rest of the UK.

What is a K code?

A K code means an amount is added to your taxable income rather than deducted. It’s used when adjustments (like a company car benefit or underpaid tax) exceed your personal allowance. K500 means £5,000 is added to your taxable income.

This post is for general information only and does not constitute financial or tax advice. For queries about your specific tax code, contact HMRC or a qualified tax adviser.