It is quite common for tax codes to be wrong, particularly if your income or employment situation has changed, so it is worth taking a few moments to check that HMRC has the correct information about you.

HMRC usually updates your tax code automatically when your income changes, using information provided by your employer. However, if HMRC has inaccurate details about your income you may be given an incorrect tax code. To fix this, ensure HMRC has your up-to-date income details and check what you need to do if you are on an emergency tax code.

If you believe your tax code is wrong, you can use HMRC’s Check your Income Tax online service to update employment details or to report income changes that might affect your tax code. For example, you can add company benefits, missing income sources, claim employment expenses and update your estimated taxable income. HMRC may then adjust your tax code based on these updates.

If you cannot access the online service, you can contact HMRC directly. Once your details are updated, HMRC will inform both you and your employer or pension provider if your tax code changes. Your next payslip should show your new code and any corrections to your pay.

At the end of the tax year, if you have paid too much or too little tax, HMRC will issue either a P800 tax calculation letter or a Simple Assessment letter to explain any refund or amount owed.