Updating your tax code

You may be put on an emergency tax code if you change jobs. HM Revenue and Customs (HMRC) will correct it automatically after you’ve given your employer details of your previous income or pension.

Your employer will get these details from your P45 - if you do not have one, they should ask you for further information.

HMRC may also update your tax code if:

If you pay too much or too little tax over the tax year, HMRC will send you a P800 or a Simple Assessment tax calculation. This will tell you how to get a refund or pay the tax you owe.

After your tax code changes

HMRC will write to you or email you if they change your tax code.

They will also tell your employer or pension provider that your tax code has changed.

Your next payslip should show:

  • your new tax code
  • adjustments to your pay if you were paying the wrong amount of tax

Tell HMRC about a change that affects your tax code

If you think your tax code might be wrong, you can use the online check your Income Tax service to tell HMRC about a change in your circumstances.

If you cannot use the online service you can contact HMRC.

If you’re contacting HMRC on someone else’s behalf

If you need to tell HMRC about a change in someone else’s circumstances (for example, because you’re their accountant) fill in a PAYE Coding Notice query form.