How to Check My Tax Code – A Comprehensive Guide

How to Check My Tax Code – A Comprehensive Guide


Understanding your tax code is essential to ensure you are paying the correct amount of tax. Many individuals are unsure about their tax code and how it affects their earnings. In this comprehensive guide, we will explain everything you need to know about checking your tax code and its significance.

1. What is a Tax Code?

A tax code is a unique combination of letters and numbers that is used by HM Revenue and Customs (HMRC) to determine how much income tax should be deducted from your earnings. The tax code reflects your personal allowances, deductions, and any other factors that affect your tax liability.

2. Where can I find my Tax Code?

Your tax code can be found on your payslip, P45, or P60. It is usually located near your National Insurance number. If you are unsure about your tax code, you can contact HMRC or your employer for clarification.

3. Understanding the Structure of a Tax Code

A tax code consists of several characters. The most common structure is a series of numbers followed by a letter. The numbers represent your tax-free allowance, while the letter indicates any additional factors that may affect your tax code.

4. Decoding the Numbers in Your Tax Code

The numbers in your tax code represent the amount of income you can earn before you start paying tax. For example, if your tax code is 1250L, the number 1250 indicates that you can earn £12,500 tax-free in a given tax year.

5. Understanding the Letters in Your Tax Code

The letters in your tax code provide additional information to HMRC and your employer. Each letter has a specific meaning that affects your tax code. Here are some common letters and their implications:

  • L – You are entitled to the standard tax-free allowance.
  • M – Marriage Allowance: You have received a transfer of 10% of your partner’s unused personal allowance.
  • N – Marriage Allowance: You have transferred 10% of your unused personal allowance to your partner.
  • T – Your tax code includes other calculations to determine your personal allowance.
  • K – Your total income is above the tax-free threshold, and your tax deductions exceed your allowances.

6. Common Tax Codes Explained

Here are some common tax codes and their meanings:

  1. 1250L – The standard tax code for most individuals with one job and no additional deductions.
  2. BR – Basic Rate: All income is taxed at the basic rate (20%).
  3. D0 – Higher Rate: All income is taxed at the higher rate (40%).
  4. D1 – Additional Rate: All income is taxed at the additional rate (45%).
  5. NT – No Taxable Income: You are not required to pay any tax.

7. Reasons Why Your Tax Code Might Be Incorrect

It is important to regularly check your tax code to ensure its accuracy. Here are some reasons why your tax code might be incorrect:

  • You have changed jobs.
  • You have multiple sources of income.
  • You have started or stopped receiving benefits.
  • You have received a tax refund.
  • You have experienced a change in your personal circumstances (e.g., marriage, divorce, or bereavement).

8. What to Do If You Think Your Tax Code is Wrong

If you believe your tax code is incorrect, you should contact HMRC as soon as possible. They will review your tax code and make any necessary adjustments. It is crucial to rectify any errors promptly to avoid underpaying or overpaying tax.

9. How to Update Your Tax Code

If your tax code needs to be updated, you can inform HMRC by using their online services or by calling their helpline. You will need to provide relevant information about your income, employment, and any changes in your circumstances.

10. Frequently Asked Questions (FAQ)

  1. Q: Can I check my tax code online?

    A: Yes, you can check your tax code online by logging into your personal tax account on the official HMRC website.

  2. Q: How often can my tax code change?

    A: Your tax code can change annually or whenever there are significant changes in your circumstances.

  3. Q: What should I do if my tax code changes?

    A: If your tax code changes, you will receive a new coding notice from HMRC. Ensure that you update your employer with the new tax code to avoid any discrepancies in tax deductions.

  4. Q: Are tax codes the same for everyone?

    A: No, tax codes vary depending on individual circumstances, such as income, allowances, and deductions.

  5. Q: Can I appeal against my tax code?

    A: Yes, if you believe your tax code is incorrect, you have the right to appeal. Contact HMRC for guidance on how to proceed with an appeal.


Checking your tax code is crucial to ensure you are paying the correct amount of tax. By understanding the structure and meaning of your tax code, you can identify any discrepancies and take the necessary steps to rectify them. Remember to regularly review your tax code and promptly contact HMRC if you suspect any errors. Stay informed and stay in control of your taxes!