Understanding UK Tax Codes: A Complete Guide

Paula Veysey-Smith • 13 February 2025

What are these jumbles of letters and numbers?


When you start a new job, receive a pension, or change employment, you’ll likely notice a tax code on your payslip. Although, to many, this code looks like a random combination of letters and numbers it is actually the crucial piece of information that determines how much tax is deducted from your income. Understanding your tax code will empower you to check that you’re paying the correct amount of tax and, if necessary, correct the code with HMRC.


What is a Tax Code?

A tax code is used by your employer or pension provider to calculate how much income tax to deduct from your pay or pension. It’s based on your Personal Allowance (the amount you can earn tax-free each year) and any other factors that affect your tax situation, such as additional income or benefits.


For the 2024/25 tax year, the standard Personal Allowance is £12,570 and will remain at this level for the 2025/6 tax year. This means most people can earn up to this amount without paying income tax.


Common UK Tax Codes and Their Meanings

Common codes can be broken down into three main categories:


Standard Tax Codes

  • 1257L: This is the most common tax code for people with one job or pension. It reflects the standard Personal Allowance of £12,570.
  • BR: Stands for Basic Rate (20%). This code is used when all your income from this employment or pension is taxed at the basic rate, usually because you have more than one job or pension and the Personal Allowance has already been used up.
  • D0: This means all your income is taxed at the higher rate (40%).
  • D1: This code applies when all your income is taxed at the additional rate (45%).
  • 0T: Used when your Personal Allowance has been used up, and all your income is taxable. Although similar to BR this code applies to all tax rates (20%, 40% & 45%).


Emergency Tax Codes

The term ‘Emergency Tax Code’ is often misunderstood.  This code is most often used when HMRC does not have the information to calculate the correct tax code for an individual and should be corrected when the information does become available. 


Usually the code 1257L W1/M1 is used which means that the Personal Allowance is being applied.  The main difference is that tax is calculated on a weekly (W1) or monthly (M1) basis rather than cumulatively. You would most usually see this if you’ve started a new job and your previous tax details are not yet available


0T W1/M1
is another emergency tax code but this means that no Personal Allowance is being applied, leading to higher tax deductions.


Worldwide and Non-Resident Tax Codes

  • NT: No tax is deducted from your income. This is usually for non-UK residents or people with special tax arrangements.
  • K: This code is used when untaxed income (e.g., state benefits or company benefits) exceeds your Personal Allowance, meaning additional tax is due.
  • If your tax code begins with an S then it is a Scottish code and similarly if it is a Welsh code it will begin with a C.


Other Special Tax Codes

There are a number of letters that may also be applied to a tax code:

  • T: Used when HMRC needs to review your tax code (e.g., for complex tax situations or multiple income sources).
  • Y: For people born before 6 April 1938 who qualify for a higher Personal Allowance.
  • L: Indicates entitlement to the basic Personal Allowance.
  • M: Given to someone receiving the Marriage Allowance from their spouse.
  • N: Given to someone transferring part of their Personal Allowance to their spouse.


How to Check and Change Your Tax Code

Your tax code will appear on your payslip, P60, or P45. If you think your tax code is incorrect, you can:

  • Check Online: Log into your personal tax account on the HMRC website.
  • Contact HMRC: Call HMRC to request a review or correction.
  • Seek Professional Advice: If you’re unsure, a tax advisor can help you navigate your tax situation.


Why Understanding Your Tax Code Matters

Getting your tax code right is essential to ensure you’re not overpaying or underpaying tax. An incorrect tax code could lead to an unexpected tax bill or a delay in receiving a refund. By understanding your tax code, you can take control of your finances and avoid unnecessary stress.


Need Help with Your Tax Code or Finances?

Tax codes can be confusing, especially if you have multiple income sources or complex financial arrangements. At MPower Accounting, we’re here to help! Our team of experts can guide you through your tax obligations, ensure your tax code is correct, and help you maximise your income.


Contact MPower Accounting today for personalised advice and support. Let us take the stress out of tax so you can focus on what matters most.



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by Paula Veysey-Smith 28 October 2025
An opportunity to sell some of your land for development can be very tempting but could you land up paying Capital Gains Tax (CGT) on your windfall. This area of tax is quite niche but knowing the rules could shape what decisions you make and it is important that you fully understand the implications. If Principal Private Residence (PPR) Relief can apply then no CGT will be due but the Revenue may well argue that is doesn’t. When does PPR apply? The relevant law is Section 222 of the Taxation of Chargeable Gains Act 1992 (TCGA 1992) . It says you don’t pay CGT on the disposal of a dwelling-house that’s been your main residence and the garden or grounds “up to the permitted area” (normally 0.5 hectares) that’s used for the reasonable enjoyment of the house. That means PPR can apply even if you sell part of your land separately — but only if it was still genuinely part of your residence at the time of disposal. However, the relief has limits: The land sold must have been enjoyed as part of the home, not used for business or rented out separately. The total area (house + garden/grounds) must not exceed 0.5 hectares (about 1.24 acres) unless a larger area is needed for the “reasonable enjoyment” of the home (which HMRC sometimes accepts for rural properties). The land must not have been sold for development before the house sale unless it clearly remains part of the residence at that time. If you sell off a piece to a developer before, or separately from, the sale of your home, HMRC can argue it’s a disposal of land and CGT would apply . HMRC’s makes its stance clear with this statement: “If the owner sells part of the garden or grounds separately from the house, relief will only apply if the land sold formed part of the garden or grounds up to the date of disposal.” How do I show that the grounds were genuinely part of the garden? If the land really is part of your garden, you can improve your position by: Showing continued use — photos, garden maintenance invoices, landscaping, etc. Avoiding any planning applications yourself before sale. Selling without fencing or subdividing it beforehand. Keeping the sale timing close to the eventual house sale (if planned). Documenting that the sale proceeds were for personal reasons , not part of a development scheme. What if planning permission is involved? If you obtain planning permission to sell at a higher value, HMRC is more likely to treat that as a capital gain so CGT will apply. If you’ve already agreed to sell the land to a developer, HMRC’s case is strong — especially if there’s planning permission or preparation for building. If you simply sold a piece of your garden that you’ve been using as part of your home, with no development activity by you , your case is stronger. However, as most developers insist on getting planning permission before the land is bought this can weaken your case. What if I’m not covered by PPR Relief? Then CGT applies on the gain you make from the sale which would be the Sales Proceeds less a portion of the original cost plus allowable expenses. Let’s look at a practical example: You bought your home + 1 acre for £400,000 total. Now you sell ¼ acre for £250,000 to a developer. You’d need to apportion the original purchase price (£100,000) to that land. Gain = £250,000 − £100,000 = £150,000. Then CGT applies at: 18% or 28% (depending on your income tax band), Less your annual CGT allowance (£3,000 for 2025/26). You can also deduct legal fees, surveyor’s fees, etc. In summary: The key factor is what the land was at the time of sale : If the sale is made before development starts, and it is still your private garden at the time of sale, PPR applies. If you had already granted rights, or if it’s no longer used as part of the garden, HMRC could argue it’s no longer part of the residence — but in your case, it’s still part of the garden when sold. Therefore, the gain should be fully exempt under PPR relief. Always seek the advice of a professional if you are considering selling land for development so that you are aware of the risks involved and the amount of CGT that may be due if PPR is not applied. Conducting the sale correctly could be the difference between a hefty tax bill or more of the funds staying in your own bank!
by Paula Veysey-Smith 16 September 2025
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White Guy Fawkes mask with a smile, black eyebrows, and pink cheeks against a black background.
by Paula Veysey-Smith 26 August 2025
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Now you can be excused if you’ve missed the announcement of the latest price increases by Xero. Apart from a rather low key “Pricing Update” notice and customer emails there has been little else published on the internet explaining the latest round of increases in the Xero Plans. So, here’s your opportunity to understand how Xero’s recent update will impact the plan you are on.
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