Complete List of UK Tax Codes and What They Mean 2026/27

As of January 2026, understanding your tax code remains essential for ensuring you pay the correct amount of income tax, yet the variety of codes issued by HM Revenue and Customs can seem bewilderingly complex. From the standard 1257L that most employees see on their payslips, to emergency codes, Scottish and Welsh variations, and specialized codes for unusual tax situations, each combination of numbers and letters tells a specific story about how much tax you should pay and why.

This comprehensive reference guide explains every UK tax code for the 2026/27 tax year. Whether you are checking your payslip and wondering what your code means, comparing codes across multiple jobs, or trying to understand why HMRC has assigned you a particular code, this article provides clear explanations with practical examples to demystify the entire system. We will cover standard codes, suffix letters, prefix codes, emergency tax codes, Scottish and Welsh variations, and special situations including K codes, 0T codes, and the rarely-seen NT code.

By the end of this guide, you will understand exactly what your tax code means, why you have it, and whether it is correct for your circumstances, empowering you to spot errors that could cost you hundreds or thousands of pounds through overpayment or unexpected tax bills.

Calculate your tax: Use our Income Tax Calculator to see how much tax you will pay with your current code, or try our Take Home Pay Calculator for a complete breakdown of your net salary after tax and National Insurance.

Key Takeaways:

• 1257L: Most common code, standard £12,570 personal allowance
• BR, D0, D1: Secondary income codes with no personal allowance at 20%, 40%, or 45%
• Emergency codes: W1, M1, or X suffixes mean non-cumulative calculation
• S and C prefixes: Scottish and Welsh taxpayers
• K codes: Deductions exceed allowances (negative personal allowance)
• 0T: No personal allowance (high earners or tax debt recovery)
• NT: No tax to pay (very rare)

Understanding Tax Code Structure: How to Read Your Code

Before examining individual codes, it is helpful to understand the structure. UK tax codes combine numbers and letters in specific patterns that convey different information about your tax position. The number typically represents your tax-free personal allowance with the last digit removed, so 1257 represents an allowance of £12,570. The letter or letters indicate your specific circumstances, such as whether you are entitled to the standard allowance, have received Marriage Allowance, or need special tax calculations.

Some codes reverse this pattern, starting with a letter prefix. The S prefix indicates you are a Scottish taxpayer subject to Scotland's distinct income tax rates and bands, while C denotes Welsh taxpayers. The K prefix is particularly important because it signals that your deductions exceed your allowances, meaning you effectively have a negative personal allowance and will pay more tax than standard calculations might suggest.

Emergency tax codes add suffixes like W1, M1, or X, which fundamentally change how your tax is calculated by applying it on a non-cumulative week-by-week or month-by-month basis rather than cumulatively across the tax year. Understanding these structural elements helps you quickly interpret any tax code you encounter and identify whether it is appropriate for your situation.

More about tax codes: The official HMRC tax codes guide provides additional detail.

Standard Tax Codes for 2026/27

1257L - The Most Common Code

The 1257L tax code is by far the most common, applying to approximately 85% of UK taxpayers who have straightforward tax affairs. This code indicates you are entitled to the full personal allowance of £12,570 for the 2026/27 tax year, the amount you can earn before paying any income tax. The government has frozen this allowance at £12,570 since the 2021/22 tax year, with the freeze extended until at least 2028, meaning it remains unchanged from previous years despite inflation.

The number 1257 represents £12,570 with the final zero removed, a formatting convention used throughout the PAYE system. The letter L specifically means you are entitled to the standard personal allowance with no adjustments. Your employer divides this allowance by your number of pay periods, so if you are paid monthly, you receive £1,047.50 tax-free each month; if paid weekly, you receive £241.73 tax-free each week.

Example: James earns £35,000 annually and has the 1257L tax code. His tax is calculated as follows: the first £12,570 is tax-free, leaving £22,430 taxable. On this amount, he pays 20% basic rate tax (£4,486 annually, or £373.83 per month if paid monthly). His monthly gross pay is £2,916.67, from which £373.83 income tax is deducted alongside National Insurance contributions, giving him a take-home pay of approximately £2,300 after all deductions.

The 1257L code is correct if you have one job or pension, earn under £100,000 (where personal allowance starts tapering), do not receive significant company benefits that need to be taxed through your code, and have not transferred or received Marriage Allowance. If any of these circumstances do not apply, you will likely have a different code that reflects your specific tax position.

1257M - Marriage Allowance Received

The 1257M code indicates you have received 10% of your spouse or civil partner's personal allowance through Marriage Allowance, a tax break designed to benefit couples where one partner earns less than the personal allowance. The M suffix adds £1,257 to your standard personal allowance, increasing it from £12,570 to £13,827.

Marriage Allowance only applies when one partner earns less than £12,570 (and therefore is not using their full personal allowance) and the other partner is a basic-rate taxpayer earning between £12,570 and £50,270. The lower-earning partner transfers 10% of their unused allowance to their higher-earning partner, who receives the benefit through the M code. The transferring partner receives the 1257N code.

Example: Sarah earns £28,000 while her husband Michael works part-time earning £9,000. Michael's income falls well below the personal allowance, so he is not using £3,570 of it. They claim Marriage Allowance, with Michael transferring 10% (£1,257) to Sarah. Sarah's code changes from 1257L to 1257M, giving her a total allowance of £13,827. This reduces her annual tax bill by approximately £251 (20% of £1,257), effectively saving the couple £251 per year. Michael's code changes to 1257N, reducing his allowance to £11,313, but since he only earns £9,000, he still pays no tax.

To claim Marriage Allowance, apply through the HMRC Marriage Allowance service. The benefit continues automatically each year unless circumstances change, such as divorce, separation, or either partner's income moving outside the eligible range.

1257N - Marriage Allowance Transferred

The 1257N code indicates you have transferred 10% of your personal allowance (£1,257) to your spouse or civil partner under Marriage Allowance. This reduces your personal allowance from £12,570 to £11,313. If you are the lower earner not using your full allowance anyway, this transfer costs you nothing in terms of actual tax paid while saving your partner approximately £251 annually.

Example: Continuing the previous example, Michael has the 1257N code showing he has transferred £1,257 to Sarah. His allowance is now £11,313, but since he earns only £9,000, he remains well within his reduced allowance and pays zero tax. The entire £1,257 transferred allowance would have gone unused on his side but provides real tax savings when applied to Sarah's higher income.

If circumstances change, for instance, if Michael gets a new job earning £20,000, the couple might want to cancel Marriage Allowance because Michael would now be paying tax himself and Sarah might no longer be a basic-rate taxpayer. The N code would revert to L (standard 1257L), restoring Michael's full personal allowance.

Non-Cumulative Emergency Tax Codes

1257L W1 / M1 / X - Emergency Tax Codes

Emergency tax codes are temporary codes HMRC assigns when they lack complete information about your employment circumstances. The most common emergency code for 2026/27 is 1257L with a W1, M1, or X suffix. While the 1257L portion gives you the standard personal allowance, the crucial difference lies in the suffix, which fundamentally changes how your tax is calculated.

The W1 suffix means "week 1" basis, your tax is calculated as if every week is the first week of the tax year, treating each pay period in isolation. M1 means "month 1" basis, doing the same for monthly-paid employees. X is used for non-standard pay periods. These suffixes make your tax calculation non-cumulative, meaning HMRC does not consider your total earnings and tax paid since the start of the tax year when calculating what you owe each pay period.

Why this can cause overpayment or underpayment: Under cumulative tax codes (the standard approach), if you earn different amounts each month, the PAYE system balances out over the year. For example, if you earn £1,000 one month and £4,000 the next, the cumulative system gives you credit for the unused personal allowance from the low-earning month when calculating tax on the high-earning month. Emergency codes cannot do this. They apply your monthly or weekly allowance (£1,047.50 per month or £241.73 per week) but cannot carry forward unused portions or give credit for tax already paid earlier in the year. This can result in either overpayment or underpayment depending on your circumstances.

Example: Rachel starts a new job in July 2026 earning £3,000 per month but does not provide her P45 from her previous employer. HMRC assigns her emergency code 1257L M1. Each month, she receives £1,047.50 tax-free, with the remaining £1,952.50 taxed at 20% (£390.50 monthly tax). However, she has already worked from April through June at her previous job, using some of her annual personal allowance there. The emergency code does not account for this. It treats every month as if it is the first month of the tax year. When Rachel eventually provides her P45, HMRC will issue a cumulative code, recalculate her year-to-date position, and refund any overpaid tax through reduced deductions in subsequent months.

How to fix emergency codes: Provide your P45 to your new employer immediately. If you do not have a P45, complete a Starter Checklist form. Contact HMRC on 0300 200 3300 or update your details in your HMRC Personal Tax Account to accelerate the correction. Emergency codes should resolve automatically within a few weeks, but if yours persists beyond two months, take action to prevent significant overpayment accumulating.

Second Job and Pension Tax Codes

BR - Basic Rate (All Income Taxed at 20%)

The BR code applies a flat 20% tax rate to all income from this source with absolutely no personal allowance applied. This is HMRC's standard code for second jobs, additional pensions, or other secondary income sources when your main employment already uses your £12,570 personal allowance. The BR code prevents you receiving your personal allowance twice, which would result in underpaying tax during the year and facing a bill later.

BR stands for "Basic Rate," referencing the 20% basic rate of income tax that applies to earnings between £12,571 and £50,270 under normal circumstances. When used as a tax code, it means every single pound you earn from this source is taxed at 20% from the very first penny. There is no tax-free amount at all.

Example: David works full-time earning £40,000 (using his 1257L code and full personal allowance there) and takes a part-time evening job earning an additional £8,000. His second employer assigns the BR code to his part-time income. Every pound of his £8,000 part-time earnings is taxed at 20%, resulting in £1,600 annual tax on that income. This is correct because David's total income is £48,000, his £40,000 main salary uses £27,430 of the basic rate band (after the £12,570 allowance), leaving £14,840 of basic rate band available. His entire £8,000 second income falls within this remaining basic rate band, so 20% is the appropriate rate.

When BR is wrong: If BR is applied to your only job or pension, you are seriously overpaying tax because you are getting no personal allowance at all. Every £1 you earn is taxed at 20% when the first £12,570 should be tax-free. Similarly, if your total income from all sources is very low, say, two part-time jobs each earning £10,000, you might want your personal allowance split between them rather than all allocated to one, which would require requesting a code change from HMRC.

D0 - Higher Rate (All Income Taxed at 40%)

The D0 code taxes all income from this source at 40% with no personal allowance, typically assigned to second jobs or additional pensions when your main employment pushes you into the higher-rate tax bracket. Higher-rate tax normally applies to income between £50,271 and £125,140, but when HMRC assigns D0, they are indicating they expect this entire income stream to fall within that bracket.

Example: Emma earns £65,000 in her main job (with 1257L code) and receives a pension from previous employment paying £12,000 annually. Her pension carries the D0 code. Here is why this is correct: her £65,000 main salary already exceeds the £50,270 higher-rate threshold by £14,730, meaning she is already into the 40% tax band. Her entire £12,000 pension income therefore falls within the higher-rate band (she is earning £77,000 total, all of which above £50,270 is taxed at 40%). The D0 code on her pension deducts £4,800 annually (40% of £12,000), which is exactly right for her total income position.

When D0 is wrong: If your combined income from all sources does not actually exceed £50,270, you are overpaying dramatically. For instance, if you have two jobs each paying £30,000 (£60,000 total), one might incorrectly get D0 when actually you should pay 20% on most of that income and only 40% on the portion above £50,270. In this scenario, having 1257L on one job and BR on the other would be more appropriate. Contact HMRC immediately if D0 is assigned but your total income does not justify it.

D1 - Additional Rate (All Income Taxed at 45%)

The D1 code taxes all income at 45%, the additional rate that applies to income over £125,140. This code is assigned to secondary income sources for very high earners when HMRC determines the entire additional income falls within the additional-rate band.

Example: Sophia earns £180,000 as a company director (with a 0T code, since her income exceeds £125,140 where the personal allowance disappears entirely). She also serves as a non-executive director for another company, earning £30,000 for that role. Her non-executive director income carries the D1 code, taxing all £30,000 at 45% (£13,500 tax). This is correct because her total income is £210,000. Every pound she earns above £125,140 should be taxed at 45%, and since her main income already exceeds that threshold, her entire non-executive income falls within the additional-rate band.

When D1 is wrong: If you are not genuinely a high earner with income exceeding £125,140, D1 causes catastrophic overpayment. Every pound is taxed at 45% when you should likely be paying 20% or 40% instead. If you see D1 and your total income is not over £125,140, contact HMRC immediately. This is a serious error that will cost you thousands in overpaid tax if left uncorrected.

No Personal Allowance Codes

0T - Zero Personal Allowance

The 0T code is one of the most commonly misunderstood tax codes because it sounds alarming but can be correct in certain circumstances. This code means you receive no personal allowance at all. Your income is taxed through the normal 20%/40%/45% bands but starting from £0 rather than after your £12,570 allowance.

The 0T code is appropriate in two main situations. First, if you earn over £125,140 annually, your personal allowance completely disappears due to the tapering mechanism. For every £2 you earn above £100,000, you lose £1 of personal allowance, meaning by £125,140, your entire £12,570 allowance has been withdrawn. Second, HMRC might use 0T when they need to collect substantial amounts of underpaid tax from previous years and removing your personal allowance is the mechanism to increase your current tax deductions sufficiently to recover the debt.

Example - High Earner: Marcus earns £150,000 as a senior manager. His income exceeds £125,140, so he has no personal allowance. The 0T code taxes his income as follows: the first £50,270 at 20% (£10,054), the next £74,870 at 40% (£29,948), and the remaining £24,860 at 45% (£11,187), totalling £51,189 in income tax annually. Compare this to someone earning £50,270 with the 1257L code who pays just £7,540. Marcus pays significantly more not only because he earns more but also because he loses the £12,570 tax-free allowance, effectively paying an extra £2,514 tax on that income (20% of £12,570).

When 0T is wrong: If you earn under £125,140 and do not owe substantial back-tax, 0T is definitely incorrect and you are massively overpaying. Contact HMRC immediately to correct it. Even if you do owe back-tax, you can request that HMRC collect it differently, such as through a Self Assessment payment plan, rather than removing your entire personal allowance if this causes financial difficulty.

NT - No Tax to Pay

The NT code is extremely rare and means no tax is deducted from this income source at all. HMRC only assigns NT in very specific circumstances where they have determined tax should not be collected through PAYE on this particular income, usually because tax is being collected elsewhere or you are genuinely not liable for UK income tax on that income.

Common situations include non-UK residents with UK income where tax treaties prevent UK taxation, certain pension arrangements where tax is collected differently, self-employed musicians and entertainers who pay tax through Self Assessment instead of PAYE, and very specific diplomatic or international organization employment where different tax rules apply.

Important warning: If you see NT on your code and you are a normal UK resident employee or pensioner, this is almost certainly wrong and you are building up a significant tax bill. NT should never apply to standard UK employment unless you have a very unusual situation. Contact HMRC immediately to investigate why NT has been assigned and correct it if it is an error. You remain liable for the tax even if it is not being deducted. HMRC will eventually identify the issue and demand back-payment, potentially with interest and penalties.

K Codes - Deductions Exceed Allowances

K codes are among the most unusual in the HMRC system because they represent negative personal allowances. Situations where your deductions exceed the allowances you are entitled to. The number following the K indicates by how much your deductions exceed allowances. For example, K500 means your deductions exceed allowances by £5,000 (represented as 500 in the code format).

K codes arise in several situations. The most common is when you have substantial taxable company benefits, such as a valuable company car, comprehensive private medical insurance, or gym membership, and the taxable value of these benefits exceeds your personal allowance. Another common scenario involves collecting underpaid tax from previous years, where HMRC reduces your allowance into negative territory to increase your current tax deductions sufficiently to recover the debt. Sometimes K codes result from receiving certain taxable state benefits alongside employment income, where the benefit pushes your total deductions above your allowances.

Example - Company Benefits: Thomas earns £45,000 and receives a company car with a benefit-in-kind value of £8,000 plus private medical insurance worth £1,200 (total benefits: £9,200). His personal allowance is £12,570, but after accounting for the £9,200 in benefits that must be taxed, his effective allowance drops to £3,370 (£12,570 - £9,200 = £3,370, represented in the tax code as 337L).

However, if Thomas had even more valuable benefits, say a £15,000 company car benefit plus various other perks totalling £18,000 in taxable benefits, his £12,570 allowance is completely used up by the benefits with £5,430 remaining. This £5,430 becomes a negative allowance, represented as K543. The K code effectively adds £5,430 to his taxable income, ensuring tax is collected on both his £45,000 salary and the £18,000 in taxable benefits.

How K codes work in practice: When you have a K code, your employer adds the K amount to your gross pay before calculating tax. Using Thomas's K543 example: his £45,000 salary is treated as if it is £50,430 for tax purposes (£45,000 + £5,430), ensuring appropriate tax is collected on his actual salary plus benefits. This results in higher monthly tax deductions than a standard code would show.

HMRC limitations on K codes: To prevent excessive tax deductions causing financial hardship, HMRC limits K code deductions to a maximum of 50% of your gross pay in any single pay period. If the K code calculation would result in deducting more than half your pay, the excess is carried forward and collected in subsequent pay periods or through other mechanisms.

When to check K codes: K codes require careful verification because errors in benefit valuations or outdated information about benefits you no longer receive can result in excessive tax deductions. Check your PAYE Coding Notice to see exactly how HMRC calculated your K code. It should itemize every benefit and deduction. If you no longer receive a benefit listed, or if the valuation seems wrong, particularly for company cars, where you should check the P11D value matches your car's actual benefit-in-kind calculation, contact HMRC immediately to correct it.

Scottish Tax Codes - S Prefix

Scottish taxpayers have an S prefix before their tax code because Scotland sets its own income tax rates and bands through the Scottish Parliament, creating a distinct tax system from the rest of the UK. While the personal allowance remains the same £12,570 UK-wide, everything above that allowance is taxed according to Scottish rates, which differ significantly from England, Wales, and Northern Ireland.

For 2026/27, Scotland operates six tax bands compared to three in the rest of the UK, creating a more progressive tax structure. The Scottish system has starter, basic, intermediate, higher, advanced, and top rate bands, with rates ranging from 19% to 48%. This complexity means Scottish taxpayers on modest incomes often pay slightly less tax than counterparts elsewhere in the UK, while higher earners pay significantly more.

Common Scottish Tax Codes

S1257L - Standard Scottish Code: This is the standard code for Scottish taxpayers entitled to the full £12,570 personal allowance. The S prefix ensures Scottish tax rates apply to income above the allowance.

Example: Fiona lives in Edinburgh and earns £30,000 with code S1257L. Her tax calculation differs from someone in England earning the same amount. After her £12,570 allowance, her taxable income is £17,430. Under Scottish rates for 2026/27, the first £2,162 is taxed at 19% (starter rate: £411), the next £10,956 at 20% (basic rate: £2,191), and the remaining £4,312 at 21% (intermediate rate: £906), totalling £3,508 in income tax. Compare this to someone in England paying £3,486 on the same income. Fiona pays £22 more annually due to Scotland's intermediate rate band.

SBR, SD0, SD1 - Scottish Second Job Codes: These work like BR, D0, and D1 but apply Scottish tax rates. SBR taxes all income at Scottish rates starting from 19%, SD0 applies higher rates, and SD1 applies top rates for very high earners with multiple incomes.

S0T - Scottish Zero Allowance: Like 0T but with Scottish rates applied. Used for high earners over £125,140 or when collecting underpaid tax.

Scottish Tax Rates 2026/27:

Who gets Scottish codes: HMRC determines your Scottish taxpayer status based on where your main residence is located. If you live in Scotland for more than half the tax year, you are a Scottish taxpayer. If you move between Scotland and the rest of the UK, notify HMRC so your code can be updated with or without the S prefix as appropriate.

Welsh Tax Codes - C Prefix

Welsh taxpayers have a C prefix (for Cymru, the Welsh word for Wales) before their tax code, indicating that Welsh income tax rates apply to their income. However, unlike Scotland's significantly different tax structure, Wales currently applies exactly the same rates and bands as England and Northern Ireland for 2026/27, meaning the C prefix makes no practical difference to the amount of tax paid.

The Welsh Government has partial control over income tax rates through the Wales Act 2017, allowing them to vary the rates by up to 10 percentage points from UK rates. However, since the power was devolved, Wales has consistently chosen to keep rates identical to England and Northern Ireland, maintaining them at 20%, 40%, and 45% for basic, higher, and additional rate bands respectively.

Common Welsh Tax Codes

C1257L - Standard Welsh Code: The standard code for Welsh taxpayers entitled to the full £12,570 personal allowance, with Welsh tax rates applied (currently identical to England/NI).

Example: Gareth lives in Cardiff and earns £40,000 with code C1257L. His tax calculation is currently identical to someone in England or Northern Ireland earning the same amount. After his £12,570 allowance, he has £27,430 taxable at 20%, resulting in £5,486 annual income tax, exactly the same as his English or Northern Irish counterparts. The C prefix exists to allow different rates in future, but for now makes no practical difference.

CBR, CD0, CD1 - Welsh Second Job Codes: These apply Welsh tax rates to second jobs and additional income sources, functioning identically to BR, D0, and D1 given current rate parity.

C0T - Welsh Zero Allowance: Like 0T but technically subject to Welsh rates (currently identical to rest of UK except Scotland).

Welsh Tax Rates 2026/27:

Who gets Welsh codes: If your main home is in Wales, HMRC should assign you a C prefix code. Check your code includes C if you live in Wales and contact HMRC if it is missing.

When Tax Codes Change and What Triggers Updates

Tax codes are not static. HMRC updates them throughout the year when your circumstances change or they receive new information affecting your tax liability. Understanding what triggers code changes helps you anticipate updates and verify they are correct when they occur.

New employment is the most common trigger. Starting a new job prompts HMRC to issue a tax code based on the information your employer provides, typically via your P45 from the previous employer or a Starter Checklist if you do not have a P45. Similarly, taking on a second job or starting to receive a pension triggers new codes for those income sources and often adjustments to existing codes to redistribute your personal allowance appropriately.

Salary changes can trigger updates, particularly significant increases or decreases. If a pay rise pushes you over £100,000 for the first time, HMRC should update your code to reflect the tapering personal allowance. Conversely, a salary decrease that drops you back below £100,000 should restore some or all of your previously tapered allowance.

Company benefits trigger code changes when you begin or stop receiving taxable benefits like company cars, private medical insurance, or accommodation. Employers report these benefits on P11D forms after each tax year ends, and HMRC typically updates codes for the following year to collect tax on the benefits. However, if you receive a new benefit mid-year, employers should notify HMRC immediately so your code can be adjusted before the following tax year.

Marriage Allowance claims cause codes to change for both partners. The transferring partner gets an N code (reduced allowance) while the receiving partner gets an M code (increased allowance). Similarly, cancelling Marriage Allowance or divorce/separation triggers codes to revert to standard allowances.

Address changes between England/Northern Ireland, Scotland, and Wales should trigger code updates to add, remove, or change the S or C prefix as appropriate, ensuring the correct tax rates apply to your new residence.

Whenever your code changes, HMRC sends you a PAYE Coding Notice explaining the new code and how it was calculated. Always read these notices carefully and verify the information is correct. Mistakes in codes can persist for months or years if you do not identify and correct them promptly.

How to Verify Your Tax Code Is Correct

Having the right tax code is crucial because even small errors compound over time into significant overpayment or underpayment. Verifying your code involves checking both the number (representing your allowance) and the letter (indicating your specific circumstances), then confirming these match your actual situation.

Start by identifying what your code should be based on your circumstances. If you have one job, no significant benefits, no Marriage Allowance, and earn under £100,000, you should have 1257L (or S1257L in Scotland, C1257L in Wales). If you have a second job, that secondary income should have BR, D0, or D1 depending on your total earnings. If you receive Marriage Allowance, you need M; if you have transferred it, you need N.

Check the number in your code matches your expected personal allowance. The standard £12,570 allowance becomes 1257 in the code. If you have received Marriage Allowance (£13,827 total allowance), your code should show 1382M. If you have transferred Marriage Allowance (£11,313 remaining allowance), you should have 1131N. If you have substantial company benefits reducing your allowance, verify the reduction matches your P11D benefit valuations.

Look for emergency code suffixes (W1, M1, X) that should not be there beyond your first few weeks in a new job. If these persist for more than two months, you are almost certainly overpaying tax because your code is not operating cumulatively.

Verify Scottish or Welsh prefixes match where you actually live. If you are in Scotland without an S prefix, or have an S or C prefix but do not live in those nations, your code needs updating.

Check your HMRC Personal Tax Account online at gov.uk/personal-tax-account where you can see exactly how HMRC calculated your code, including all the components that contributed to it. This detailed breakdown makes it much easier to spot errors, such as benefits you no longer receive still being factored in, or income from jobs you have left still being considered.

If you identify errors, contact HMRC immediately through your Personal Tax Account online (fastest method), by phone on 0300 200 3300, or via your employer who can liaise with HMRC on your behalf. Do not delay. Every month you remain on the wrong code means additional overpayment or underpayment accumulating.

Final Thoughts

Understanding your tax code is essential for ensuring you pay the correct amount of tax. Whether you have the standard 1257L, a Marriage Allowance variation, a second job code, or a K code, knowing what your code means empowers you to verify its accuracy and correct errors promptly.

For a full view of your tax position, see our Income Tax Calculator. For help understanding your payslip, see our PAYE payslip guide.

Official Sources and Further Reading

GOV.UK Official Guidance:

• HMRC Tax Codes Overview - Complete official guidance on all UK tax codes
• What Your Tax Code Means - Letter-by-letter explanation from HMRC
• Emergency Tax Codes - When and why emergency codes apply
• How to Update Your Tax Code - Official process for corrections
• HMRC Personal Tax Account - Check your code and tax position online
• Income Tax Rates and Allowances - Current tax rates and bands

Scottish and Welsh Tax Information:

• Scottish Income Tax - Rates and bands for Scottish taxpayers
• Welsh Income Tax - Information for Welsh taxpayers

This guide provides general information about UK tax codes for 2026/27. Individual circumstances vary. For personalised advice about your specific situation, consult a qualified tax adviser or contact HMRC directly. Always check GOV.UK for current rates and guidance.