UK Tax Codes Explained: What Your Tax Code Means in 2025/26 & 2026/27

Your tax code is a short combination of numbers and letters that tells your employer how much income tax to deduct from your pay. Getting it right is crucial — the wrong code means you either overpay tax (giving HMRC an interest-free loan) or underpay (meaning a surprise bill later). Around 1 in 3 UK workers has been on the wrong tax code at some point, so it's worth understanding yours.

How Tax Codes Work

A tax code has two parts: a number and one or more letters. The number represents your tax-free allowance — multiply it by 10 to get the actual figure. The letters indicate your circumstances.

For example, the code 1257L means:

1257 — Your tax-free personal allowance is £12,570 per year (1257 × 10)
L — You're entitled to the standard personal allowance with no special circumstances

Your employer takes this code and spreads the allowance across each pay period. On a monthly payroll, £12,570 ÷ 12 = £1,047.50 of your monthly salary is tax-free. Everything above that is taxed at the appropriate income tax rate.

The Standard Tax Code for 2025/26: 1257L

The vast majority of UK employees have the tax code 1257L. This has been the standard code since 2021/22, as the personal allowance has been frozen at £12,570 since then (and is expected to remain frozen until at least April 2028).

You'll have 1257L if you:

Have one job or pension
Don't receive taxable state benefits
Don't have any company benefits (car, private medical, etc.)
Haven't applied for Marriage Allowance
Don't owe tax from a previous year

If your tax code is anything other than 1257L, it's worth understanding why.

Complete Guide to Tax Code Letters

Standard Letters

Letter	Meaning	Who Gets It
L	Standard personal allowance	Most employees with one job and no special circumstances
M	Marriage Allowance received	Higher-earning partner who's received £1,260 allowance transfer. Your code would be 1319M (£13,190 allowance)
N	Marriage Allowance transferred	Lower-earning partner who's given away £1,260. Your code would be 1194N (£11,940 allowance)
T	Other calculations needed	HMRC needs to review items in your code, or your allowance exceeds a certain amount

Special Codes (No Number)

Code	Meaning	When It's Used
BR	All income taxed at 20% (basic rate)	Second job, pension, or employer doesn't have your P45. No tax-free allowance applied.
D0	All income taxed at 40% (higher rate)	Second job or pension where the first already uses your full allowance and basic rate band
D1	All income taxed at 45% (additional rate)	Third income source or very high earner with allowance used elsewhere
0T	No personal allowance	New job with no P45, personal allowance fully used by another source, or income above £125,140
NT	No tax deducted at all	Rare — usually for specific circumstances where income is taxed elsewhere (e.g. some diplomats)

Country Prefixes

Prefix	Meaning	Example
S	Scottish Income Tax rates apply	S1257L — standard allowance but taxed at Scotland's 6 tax bands
C	Welsh Income Tax rates apply	C1257L — currently Welsh rates match England/NI, but the prefix allows future divergence

The K Code

A K code is unusual — it means you owe HMRC more tax than your personal allowance covers. This happens when the value of your taxable benefits (company car, medical insurance, etc.) exceeds your tax-free allowance.

For example, K475 means £4,750 is added to your taxable income rather than subtracted from it. Your employer can't deduct more than 50% of your salary through a K code in any pay period, so if the amount is very large, HMRC may collect some separately.

Emergency Tax Codes

If you start a new job and your employer doesn't have your P45 or the right information from HMRC, you'll be put on an emergency tax code. These have W1 (weekly paid) or M1 (monthly paid) at the end, or sometimes X.

Common emergency codes:

1257L W1 or 1257L M1 — You get the standard allowance but calculated on a non-cumulative basis
BR M1 — All income taxed at 20% with no allowance
0T M1 — No allowance, taxed at all rates

What "Non-Cumulative" Means

Normally your tax is calculated cumulatively — HMRC looks at your total earnings for the year so far and works out the right amount of tax. With an emergency code (W1/M1), each pay period is treated independently. This means:

If you started mid-year, you won't get the benefit of unused allowance from earlier months
You'll almost certainly overpay tax initially
Once HMRC sorts your code (usually within 2-6 weeks), your employer will refund the overpaid tax through your salary

How to Speed Up the Fix

Give your new employer your P45 from your previous job as soon as possible
Complete a Starter Checklist (previously P46) if you don't have a P45
Log into your HMRC personal tax account and check your tax code is updating
Call HMRC on 0300 200 3300 if it hasn't been corrected within a month

Where to Find Your Tax Code

Payslip — Usually printed near the top, next to your NI number and employee reference
P60 — Your end-of-year tax summary, issued by your employer by 31 May each year
P45 — Given when you leave a job, showing your tax code and earnings to date
HMRC personal tax account — The most reliable source. Log in at gov.uk/personal-tax-account
HMRC app — The free HMRC app shows your current tax code and allows you to check past codes
Tax code notice (P2) — HMRC sends this by post or to your online account when your code changes, usually in January/February before the new tax year

Common Reasons for a Wrong Tax Code

HMRC processes millions of tax codes, and mistakes happen. Common reasons:

Starting a new job — No P45 provided, so emergency code applied
Multiple jobs — Allowance split incorrectly between employers, or not allocated at all
Company benefits changed — New company car, lost medical insurance, etc. not reflected
Marriage Allowance errors — Applied when no longer eligible, or not applied when you are
Previous year's underpayment — HMRC collecting owed tax through your code
Pension income starting — Second income source not properly coded
Earnings estimate wrong — HMRC estimated your earnings higher or lower than reality

How to Check and Fix Your Tax Code

Log into your HMRC personal tax account — This shows your current code and what it's based on
Review the breakdown — HMRC shows you exactly what's included: personal allowance, benefits, adjustments. Check each item.
Report any errors online — You can update your income estimate, report benefit changes, and correct other details directly
Call HMRC on 0300 200 3300 (Monday to Friday, 8am to 6pm) if you can't fix it online
Wait for confirmation — HMRC will issue a new tax code notice. Your employer must use the new code from the date HMRC specifies.

Important: your employer cannot change your tax code. Only HMRC can issue a new code. If you think your code is wrong, contact HMRC directly — not your payroll department.

How Tax Codes Affect Your Take-Home Pay

The difference between tax codes can be significant. Here's how much a person earning £35,000 would take home under different codes:

Tax Code	Tax-Free Amount	Annual Tax	Monthly Take-Home
1257L (standard)	£12,570	£4,486	~£2,543
1100L (reduced)	£11,000	£4,800	~£2,517
BR (all basic rate)	£0	£7,000	~£2,333
0T (no allowance)	£0	£7,000	~£2,333
K475 (benefits)	-£4,750	£7,950	~£2,254

That's a difference of nearly £300/month between the standard code and a K code — so it's well worth checking yours is correct.

Use our salary calculator to see exactly how your tax code affects your take-home pay. You might also want to understand how National Insurance affects your deductions, or check whether you're eligible for Marriage Allowance to reduce your partner's tax bill.