How do I tell HMRC my Tax Code is Wrong?

A number of reasons can result in you ending up with the wrong tax code which can often mean you will pay an incorrect amount of tax.

To pay the right amount of tax from PAYE income hinges on having the correct tax code.

The tax code used by your employer (or other income source like a pension) can originate from HMRC or the employer who might use a standard code based on regulations defined by HMRC.

Either way verifying that your employer is using the appropriate tax code for you is crucial and HMRC will need to be contacted if your tax code is wrong.

When contacting HMRC you should provide all the necessary, accurate information so they can work out your correct tax code.

What do I need to tell HMRC that my tax code is wrong?

It’s recommended to gather together as many of these details below as you can before you contact HMRC:

  • Full name (including middle names).
  • Date of birth.
  • Email address.
  • National insurance number.
  • Employer/pension provider tax reference number.
  • Employee works number or pension number (private and/or company).
  • Estimate of total income for current tax year.
  • Company benefits (e.g. health care, car fuel allowance).
  • Any other income (e.g. savings interest, property rental).
  • Weekly state benefits or state pension payments.

How do I know if my tax code is incorrect?

You can gain access to the workings of your tax code through your personal tax account or the HMRC app which is available for both apple and android devices.

If you think previous tax years need checking you can do this online as well by logging in through your government gateway account.

Your tax free personal allowance is an important part of how your tax code is calculated and should be assessed at the same time as checking your tax code.

Why is my tax code wrong?

Your tax code is something that can be wrong for numerous different reasons including changing your job, company benefits and an increase or decrease in your taxable earnings.

Sometimes HMRC will not be able to issue you with an accurate tax code because they don’t have all of the information they need to make the necessary changes.

This is where you come in and need to check your tax code regularly especially if you have a change in circumstances.

The tax office places the responsibility on you to let them know about certain amendments and if you don’t you will continue to over or underpay income tax.

Why does my tax code matter?

If you are a taxpayer who has a tax code error it is likely that you are paying the wrong amount of income tax.

A tax code that is too low (or you were given an emergency tax code when you shouldn’t have) usually means you will pay too much tax.

You can reclaim the overpayment of tax as long as you are within HMRC’s deadlines.

If you have a tax code that is too high you will not be paying enough tax and HMRC will normally recover the tax you owe via a new tax code.

Either way it is better to find out sooner than later so your current tax code can be increased or decreased to match your circumstances.

How to tell HMRC that your tax code is incorrect

As soon as you realise there has been a mistake with your PAYE tax code or you have had a change in circumstances you must get in touch with HMRC online or by phone on 0300 200 3300.

HMRC let’s you tell them about a change in your income that could affect your current tax code by using their check your income for the current tax year online service.

What happens after I have told HMRC about my incorrect tax code?

When you have asked for a review of your tax code HMRC will check your tax record and make appropriate adjustments.

They will then electronically send your employer (or pension provider) a new tax code to be used the next time you are paid.

If you have overpaid income tax in the current tax year because of an incorrect code you should receive this back automatically in your next pay (after your new tax code has been operated).


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