Why Am I Assigned The D0 Cumulative Tax Code?

If you are concerned about being assigned the D0 cumulative tax code and are wondering about the reasons for it being assigned to your earnings, you will find detailed guidance in the following blog post that will explain the possible reasons for being assigned this tax code. In addition to this, we will also explore the possibility of being overtaxed due to being assigned the D0 cumulative tax code and will review your options as a taxpayer to rectify the situation.

Why Am I Assigned the D0 Cumulative Tax Code?

To understand the reason(s) why your tax code is D0 Cumul or D0 Cumulative, we will break the tax code into two parts. The first part of your tax code is D0. There are many reasons why you could be assigned the D0 tax code. These include the following possibilities:

  • working at two jobs and the D0 Cumulative tax code is assigned to your second job
  • receiving two separate incomes through a job and a pension
  • the entire income being taxed without deduction of Personal Allowance 
  • gross earnings being between £37,701 and £150,000
  • being taxed at the higher rate of 40%

The second part of your tax code is the cumulative nature assigned to it. 

If your tax code is cumulative, it means that your tax payments made throughout the year are taken into account. This includes the amount of tax-free allowance you have used during the same time. Any unused personal allowance can be carried forward to future weeks. 

You can easily identify a cumulative tax code by checking the letters at the end of the code. If your tax code ends with X, W or M, it is not cumulative. If it does not have any of these letters, then it is cumulative.

Based on the above dissection of your D0 cumulative tax code, it may be safe to say that the most common reason for being assigned this tax code is possibly the fact that you have two sources of income; either through two jobs or a job and a pension and the D0 cumulative tax code is being assigned to your second job.

The D0 tax code indicates that the entirety of the individual’s income will be taxed at 40%, as their tax-free Personal Allowance of £12,750 has already been utilised for their primary source of income.

It is important to note that this is only applicable if the income from the second job is subject to a higher tax rate of 40%. 

Could I Be Overpaying My Tax If My Tax Code Is D0 Cumul?

Yes, there is a fair chance that you could be overpaying your tax if your tax code is D0 cumulative. However, being assigned the D0 cumulative tax code alone is usually not the cause of overpaying your taxes as there could be additional reasons such as the following that cause overpaid taxes: 

  • incomplete or incorrect documents
  • switching from a full-time job to a part-time job
  • not updating a change of circumstances with HMRC
  • an error in being assigned the tax code by your employer

In this case, you should inform your employer as well as the HMRC to avoid being overtaxed. If your second source of income is through self-employment, you should contact HMRC directly and have the error corrected. 

You can do this by either calling them on their helpline at 0300 200 3300 or using the HMRC income tax checker tool online by accessing your Personal Tax Account. 

What Happens If You Overpay Your Taxes Due To The D0 Cumulative Tax Code?

If you find yourself in a situation where you have overpaid your taxes due to the D0 tax code being assigned to you, there is a way for you to claim a refund from the HMRC. 

The process involves filing a formal application and providing evidence to support your claim. This can be done via an online application for a tax refund.

It is important to note that you will need to provide detailed information about your employment and reasons why you believe the tax code assigned to you is incorrect.

If your application is approved, you will receive a confirmation letter from the HMRC and can expect to receive your tax refund after the end of the tax year.

If you plan on taking up a second job, it’s important to follow these instructions to avoid being overtaxed. Firstly, you must obtain a Starter For or P46 form from your new employer, which is used to update your employment details at the HMRC. 

Additionally, you should confirm the tax codes assigned to both of your jobs. Generally, your main job will be assigned a 125L tax code for 2022-2023, while your second job will be given a BR, D0 or D1 tax code.


The above discussion helps to conclude that there are many reasons why you may be assigned the D0 cumulative tax code but the most common is that you are working at two jobs and your second job is assigned the D0 tax code as your earnings are being taxed at the higher rate of 40%.


What is a D0 tax code?

Tax Code D0 – Tax Rebate Services

UK Tax Codes Explained | What Should My Tax Code Be? – Brian Alfred