How to Check Your Tax Code – A Comprehensive Guide

How to Check Your Tax Code – A Comprehensive Guide


Welcome to our comprehensive guide on how to check your tax code. Understanding your tax code is crucial to ensure that you are paying the correct amount of tax and avoid any potential penalties. In this article, we will explain the importance of tax codes, how to find your tax code, and what to do if you discover any discrepancies. Read on to become a tax code expert!

1. What is a Tax Code?

A tax code is a 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. It is unique to each individual and can change over time based on various factors such as employment status, income level, and allowances.

2. Why is Your Tax Code Important?

Your tax code is important because it determines how much tax you need to pay. If your tax code is incorrect, you may end up paying too much or too little tax, which can lead to financial issues and potential penalties from HMRC. Therefore, it is crucial to regularly check your tax code to ensure its accuracy.

3. Where Can You Find Your Tax Code?

Finding your tax code is relatively easy. Here are a few places where you can locate your tax code:

  1. Pay Slip: Your tax code is usually mentioned on your pay slip, along with your other payroll information.
  2. P60 Form: Your P60 form, which you receive at the end of each tax year, also displays your tax code.
  3. Personal Tax Account: You can access your personal tax account on the HMRC website to view your tax code.
  4. Tax Coding Notice: HMRC may send you a Tax Coding Notice by post, which will contain your tax code.

4. How to Decode Your Tax Code

Your tax code consists of several letters and numbers, each representing a specific piece of information. Here is a breakdown of the most common tax code components:

  • Numeric Component: The numeric component of your tax code represents your tax-free allowance, which is the amount of income you can earn without paying tax.
  • Letter Component: The letter component provides additional information about your situation, such as if you have multiple jobs or certain allowances.
  • Emergency Tax Code: If your tax code is followed by the letter ‘L’, it means you are on an emergency tax code, and your income is being taxed at a higher rate until your correct tax code is applied.

5. Common Tax Code Mistakes

It is not uncommon for tax codes to contain errors. Here are some common mistakes that can occur:

  • Incorrect Personal Allowance: Your personal allowance may not be accurately reflected in your tax code, resulting in overpayment or underpayment of tax.
  • Outdated Coding: If HMRC has not received up-to-date information about your employment or income changes, your tax code may be outdated.
  • Multiple Jobs: If you have more than one job, it is essential to ensure that your tax code is adjusted correctly to avoid overpaying or underpaying tax.

6. How to Correct Your Tax Code

If you believe that your tax code is incorrect, it is crucial to take action to rectify the situation. Here are the steps you can follow:

  1. Contact Your Employer: Start by contacting your employer or payroll department to discuss the issue and provide them with any necessary information.
  2. Inform HMRC: If the error persists, you should contact HMRC directly and inform them about the problem. They will guide you on the next steps to take.
  3. Keep Documentation: Throughout the process, it is essential to keep copies of any correspondence, payslips, or other relevant documents as evidence.

7. Frequently Asked Questions (FAQ)

  1. Q: How often can my tax code change?
  2. A: Your tax code can change at any time, depending on various factors such as changes in your income, employment status, or tax regulations. It is important to regularly check your tax code to ensure it is up to date.

  3. Q: Can I calculate my own tax code?
  4. A: While it is possible to calculate an estimate of your tax code based on your income and personal circumstances, it is recommended to rely on HMRC’s official tax code issued to you.

  5. Q: How can I contact HMRC regarding my tax code?
  6. A: You can contact HMRC by phone, online chat, or through their website’s contact form. Make sure to have your National Insurance number and other relevant information ready when reaching out to them.

  7. Q: What should I do if I have overpaid tax?
  8. A: If you have overpaid tax, you can claim a refund from HMRC. Contact them directly or use their online services to initiate the refund process.

  9. Q: Is there a penalty for having an incorrect tax code?
  10. A: There can be penalties for having an incorrect tax code, especially if the error is due to deliberate actions or negligence. It is important to rectify any discrepancies as soon as possible to avoid penalties.


Checking your tax code is an essential task to ensure that you are paying the correct amount of tax. By following the steps outlined in this comprehensive guide, you can easily check your tax code, understand its components, and take action if any errors are detected. Remember, staying proactive with your tax affairs will help you avoid unnecessary financial complications.