UK Tax Code Explained 2026: What Every Letter and Number Means

Chandraketu Tripathi

Finance Editor, Kaeltripton

Published 4 Apr 2026

Last reviewed 4 May 2026

✓ Fact-checked

By Chandraketu Tripathi | Updated April 2026

Your UK tax code tells your employer how much income tax to deduct from your pay under PAYE. Get it wrong and you could pay too much tax — or face a bill at year end. This guide decodes every tax code format in 2026-27: what the numbers mean, what the letters mean, what the suffixes mean, and what to do if yours is wrong.

Key Facts

Most common tax code 2026-27: 1257L | Means: £12,570 tax-free personal allowance, standard entitlement | Check your code: tax.service.gov.uk | Wrong code? Call HMRC: 0300 200 3300

How to Read a UK Tax Code

Most UK tax codes have two parts: a number and a letter. The number represents your tax-free income divided by 10. So 1257 = £12,570 personal allowance. The letter indicates what type of allowance or situation applies. For example: 1257L = £12,570 allowance, standard entitlement. 1508M = £15,080 allowance (Marriage Allowance received). 500T = £5,000 allowance (temporary or complex situation).

UK Tax Code Letters Explained 2026

Letter	What It Means	Example
L	Standard personal allowance — most common	1257L
M	Marriage Allowance received from spouse (+£1,260)	1508M
N	Marriage Allowance transferred to spouse (−£1,260)	1006N
T	Complex tax situation — HMRC calculates personally	500T
S	Scottish income tax rates apply	S1257L
C	Welsh income tax rates apply (Cymru)	C1257L
K	Negative allowance — untaxed income exceeds allowance	K497
0T	No personal allowance — either all used or emergency	0T
BR	All income taxed at basic rate (20%) — second job	BR
D0	All income taxed at higher rate (40%) — second job	D0
D1	All income taxed at additional rate (45%)	D1
NT	No tax — exempt from income tax	NT
W1 / M1	Emergency code — week/month basis only	1257L W1

Most Common Tax Codes UK 2026-27

Tax Code	Who Has It	What It Means
1257L	Most UK employees and pensioners	Standard £12,570 personal allowance
S1257L	Scottish taxpayers	Standard allowance, Scottish rates
1508M	Marriage Allowance recipients	£15,080 allowance — received transfer
1006N	Marriage Allowance transferors	£10,060 allowance — transferred to spouse
BR	Second job / additional income	All taxed at 20% — no allowance here
0T	No allowance — emergency or all used	All income taxed from £0
K codes	Company car, other benefits	Untaxed benefits added to income
NT	Non-taxable income	No tax deducted

What to Do If Your Tax Code Is Wrong

Check your tax code on your payslip, P60, or at tax.service.gov.uk (Personal Tax Account)
Contact HMRC on 0300 200 3300 if you believe your code is incorrect
Update your details online via your Personal Tax Account — changes to income, benefits, or allowances
Check your P800 — HMRC sends an annual reconciliation after the tax year ends; if you've overpaid, you'll get a refund automatically
Don't ignore it — underpaying tax due to a wrong code means HMRC will collect the difference the following year, potentially through a lower personal allowance

Frequently Asked Questions

What is tax code 1257L?

1257L is the most common UK tax code for 2026-27. The number 1257 represents your tax-free personal allowance of £12,570 (the last digit is dropped). The letter L means you are entitled to the standard personal allowance. So 1257L means you can earn £12,570 before paying any income tax — HMRC divides this by your pay periods and deducts tax accordingly via PAYE.

What does the M or N suffix on a tax code mean?

M suffix (e.g. 1508M) means you have received a Marriage Allowance transfer from your spouse — your personal allowance has increased by £1,260 (their transferred amount). N suffix (e.g. 1006N) means you have transferred Marriage Allowance to your spouse — your personal allowance has reduced by £1,260.

What is an emergency tax code?

Emergency tax codes in 2026-27 are typically W1, M1, or X. These are applied when HMRC doesn't have enough information about your income — usually when you start a new job without a P45. W1/M1 means you are taxed on a week-by-week or month-by-month basis without considering the full year's allowances. This can mean overpaying tax temporarily. Give your employer a P45 or a Starter Checklist to get a normal code.

How do I check my tax code is correct UK?

Check your tax code on your payslip, P60, or via your HMRC Personal Tax Account at tax.service.gov.uk. If your code seems wrong — especially if you've changed jobs, started or stopped receiving benefits in kind, or claimed Marriage Allowance — call HMRC on 0300 200 3300 or update your details online. An incorrect tax code can mean overpaying or underpaying thousands of pounds.

What does a K tax code mean UK?

A K code (e.g. K497) means you have income that is not being taxed elsewhere — usually benefits in kind (like a company car) that exceed your personal allowance. Unlike standard codes, K codes add to your taxable income rather than reducing it. The K number is the amount added to your income for tax purposes. Your employer deducts the resulting tax from your salary, but there is a 50% rule — they cannot deduct more than 50% of your gross pay in any pay period.

Related Articles

Disclaimer: Always verify with GOV.UK, HMRC, Acas, and NHS. Sources: gov.uk, acas.org.uk, theemploymentlawsolicitors.co.uk, moneysavingexpert.com, nhsbsa.nhs.uk, nhs.uk, raisin.com, puremagazine.co.uk. April 2026.