UK Tax Codes Explained 2026 — 0T, 1257L, BR, K, NT

If you’ve ever stared at your payslip and thought “what does 1257L actually mean?”, you’re not alone. In 12 years placing UK candidates, the question I get asked most after “what salary should I push for?” is “is my tax code right?”

Wrong tax codes cost real money. I’ve had candidates overpay £2,000+ in their first year at a new job because nobody told them their 0T code was temporary. Others have been undertaxed and got hit with a year-end bill they couldn’t afford. The fix is usually one phone call.

Here’s how UK tax codes actually work in 2026/27, what every code means, and exactly what to do when yours looks wrong.

The structure: number + letter

A UK tax code has two parts:

The number = your tax-free allowance ÷ 10. So 1257 means £12,570 tax-free a year (the standard Personal Allowance). 1383 means £13,830 (you have an extra allowance). 0 means no allowance.

The letter = how the allowance is applied. L is the standard letter. M and N relate to Marriage Allowance. T means there’s an unusual adjustment. K means you owe tax. BR / D0 / D1 set a flat rate. NT means no tax at all.

Your employer takes the code and runs it through HMRC’s payroll software. The software works out how much tax to deduct each pay period.

The standard: 1257L

If you have one job, no company benefits, and no quirks in your tax history, you’ll be on 1257L. The Personal Allowance is frozen at £12,570 until April 2028, so this code has been the same for several years now.

What it does:

• Gives you £12,570 tax-free a year
• Splits that across your pay periods (£1,047.50/month if you’re paid monthly, £241.73/week if weekly)
• Applies cumulatively — if you earn nothing in April, your unused allowance rolls into May

If you’re on 1257L and your job is straightforward, you don’t need to do anything. The system works.

Quick check your take-home pay — see what 1257L actually puts in your pocket on any salary with the UK PAYE take-home calculator. It uses 2026/27 rates and shows the tax breakdown line by line.

0T — the no-allowance code

0T means zero allowance. You’re taxed from the first £1.

Why HMRC issues it:

• You started a new job without giving your P45 or completing a Starter Checklist
• You have multiple income sources and HMRC has used your allowance elsewhere
• You’ve earned over £125,140, where the Personal Allowance tapers to zero
• You’re a temporary or holding code while HMRC processes a change

The variants you’ll see in payslips:

• 0T — cumulative, taxes you on the running year-to-date assumption that you have no allowance
• 0T W1 / 0T M1 / 0T X — non-cumulative, taxes each pay period in isolation (the W1, M1, X mean Week 1 / Month 1 / Emergency basis)
• 0T non-cumulative — same as 0T W1 / M1, just spelled out

The non-cumulative 0T is particularly punishing. It ignores any tax-free pay you’d already had earlier in the year and starts each pay period from scratch. Most people overpay 20-40% in tax for as long as they’re on it.

The fix is fast: hand your new employer your P45 from your last job, or complete the Starter Checklist (gov.uk has the form). HMRC reissues the correct code within 5 working days, and any overpaid tax comes back through your wages automatically.

BR — basic rate

BR means everything from this income source is taxed at 20% with no allowance.

BR is correct for second jobs and most pensions, because your main job has already used your Personal Allowance. If you have a £40k main job and a £8k weekend job, putting your full £12,570 allowance against the main job and BR-coding the second job is the right answer.

BR is wrong if:

• It’s on your only job
• You started a new job mid-year and HMRC hasn’t reissued your code yet

If BR is on your only employment, fix it through your Personal Tax Account or call HMRC on 0300 200 3300.

D0 and D1 are higher-rate variants of BR — D0 taxes everything at 40%, D1 at 45%. Same rules apply: correct for additional employments where the main income has used lower bands.

K codes — you owe tax

K codes are the only codes where the number is added to your taxable pay rather than subtracted. They mean you have negative tax-free pay.

Common reasons:

• Company car benefit (the higher the CO₂, the bigger the K addition)
• Medical insurance, gym membership, or other benefits in kind
• Tax you owed from a previous year being collected through your code
• State pension that hasn’t been taxed at source

How K codes work in practice:

• K500 means £5,000 is added to your taxable pay each year (£416.67/month)
• Your tax bill goes up because you’re effectively being taxed on a higher figure than you actually earn
• The maximum K code can never deduct more than 50% of your gross pay in any pay period — that’s a legal cap to stop people getting payslips with zero net pay

If a K code surprises you, check your Personal Tax Account for the breakdown. The most common cause I see for new K codes is a company car that’s been added but the value seems wrong — usually a CO₂ bracket question worth asking HR about.

M and N — Marriage Allowance codes

The Marriage Allowance lets one spouse or civil partner transfer 10% of their unused Personal Allowance (£1,260 in 2026/27) to the other.

• The giver (lower earner) gets a code ending in N — their allowance reduces by £1,260
• The receiver (higher earner, but still a basic-rate taxpayer) gets a code ending in M — their allowance increases by £1,260

So 1383M means £13,830 tax-free. That’s £252 a year in tax savings — small but free money once you’ve applied.

Eligibility (2026/27):

• One partner earns under £12,570 (or doesn’t pay tax at all)
• The other partner earns between £12,571 and £50,270 (basic rate)
• You’re married or in a civil partnership (not just cohabiting)

Apply at gov.uk/marriage-allowance. The lower earner makes the application.

NT — no tax

NT is the no-tax code. No income tax is deducted at all from this employment. It’s rare and applies in narrow circumstances:

• Certain pensions (some state pensions, some foreign pensions)
• Foreign workers under specific double-taxation treaties
• Income paid abroad where tax is paid in another country

National Insurance is still deducted normally on NT — only the income tax is zero.

If you’ve been put on NT and you don’t think it’s right, get it checked urgently. Owing a year’s tax all at once at year-end is brutal.

T — there’s something unusual

T is HMRC’s “wait, there’s a complication here” letter. Common reasons:

• You earn between £100,000 and £125,140 (Personal Allowance tapering)
• You have several income sources and HMRC is using a custom split
• Your personal allowance has been adjusted for unusual reasons

A T code isn’t wrong — it just signals HMRC has done a custom calculation. Open your Personal Tax Account to see the breakdown.

Emergency tax codes — what they look like

When HMRC doesn’t have enough information, you’ll see one of these:

Code	Meaning
1257L W1	Standard allowance, taxed weekly in isolation
1257L M1	Standard allowance, taxed monthly in isolation
1257L X	Same as W1/M1 — emergency basis
0T W1 / 0T M1	No allowance, non-cumulative — strictest emergency code

The W1/M1/X suffix is the key. It means non-cumulative — each pay period is treated as a fresh start, ignoring what you’ve already earned in the year. You’ll usually overpay tax until HMRC fixes the code.

These are temporary. Once HMRC has your P45 or Starter Checklist, they remove the W1/M1/X and you’re on a normal cumulative code. Overpaid tax is refunded through your wages.

How to fix a wrong tax code (the real-world version)

1. Sign in at gov.uk/personal-tax-account with your Government Gateway ID.
2. Look at your current PAYE tax code in the Income Tax section. It shows the breakdown — Personal Allowance, any benefits, any adjustments.
3. Compare against reality. Standard one-job employee, no benefits, no Marriage Allowance? Should be 1257L. Anything else, check why.
4. For simple fixes (wrong company car amount, missing Marriage Allowance, etc.) update directly in your Personal Tax Account. Most fixes go live in the next 5 working days.
5. For complex situations (multiple jobs, mid-year changes, K codes) call HMRC on 0300 200 3300 (Mon-Fri 8am-6pm). Have your NI number, payslip, and P60 ready.
6. Wait for the new code to come through on your next payslip. Refunds are automatic.

What I tell candidates after they accept an offer

Three things, every time:

1. Hand over your P45 on day one. If you don’t have one (first UK job, recently abroad), complete the Starter Checklist before payroll cutoff. This is what stops you getting put on 0T.
2. Check the first payslip. If the code is anything other than what you expected, screenshot it and email HR/payroll the same day. Don’t wait three months and find you’ve overpaid £1,500.
3. Sign in to your Personal Tax Account at the start of every tax year. It takes five minutes and catches the slow-burn problems — wrong company car valuations, ghost benefits HMRC thinks you have, leftover K code adjustments from years ago. (If this is your first payslip in a brand-new field, the changing-occupations master hub handles the rest of the moving-into-a-new-job admin the recruiter forgot to mention.)

Per-code deep dives

For full detail on any individual code, see the dedicated page:

• 1257L — standard
• 0T — no allowance / emergency
• BR — basic rate flat 20%
• D0 / D1 — higher / additional rate flat
• K codes — negative allowance
• M / N — Marriage Allowance
• T — custom adjustment
• NT — no tax
• W1 / M1 — emergency basis suffix
• S1257L / SBR — Scottish prefix
• C1257L — Welsh prefix
• Full UK tax codes index — every code one click away

Related calculators

• UK net wage calculator — see what any salary nets you after 1257L tax, NI, student loan
• UK Bonus Tax Calculator — work out the actual hit on a £5k or £10k bonus
• UK Salary Sacrifice Calculator — pension salary sacrifice tax savings
• UK Pay Rise Calculator — see the after-tax value of a £3k or £5k rise

Common UK tax codes — at a glance

Code	Meaning	When it’s used
1257L	£12,570 allowance, standard	One job, no benefits, no quirks
1257L W1/M1/X	£12,570 emergency basis	Mid-year start, no P45
0T	No allowance	Missing details, very high earner
0T W1/M1	No allowance, non-cumulative	Strict emergency code
BR	All taxed at 20%	Second job, basic-rate
D0	All taxed at 40%	Second job, higher-rate
D1	All taxed at 45%	Second job, additional-rate
K500	Negative allowance (-£5,000)	Benefits exceed allowance
M / 1383M	Marriage Allowance receiver	Spouse transferred allowance
N	Marriage Allowance giver	Transferred to spouse
T	Custom adjustment	High earner, complex case
NT	No tax deducted	Specific pensions, treaties
S1257L	Scottish standard	Scottish taxpayer
C1257L	Welsh standard	Welsh taxpayer

The bottom line

Tax codes look intimidating but they’re mechanical. Three things to remember:

1. The number is your allowance ÷ 10. Bigger number = more tax-free pay.
2. The letter is the rule. L is standard. M / N are Marriage. K is “you owe”. BR is basic rate at all income.
3. Wrong codes self-correct once HMRC has your details. Don’t ignore them, but don’t panic either — overpaid tax comes back automatically.

If your code looks wrong and you’re not sure, the Personal Tax Account is the fastest way to see what’s going on. Most fixes are five-minute jobs.