The easiest route: Personal Tax Account
If you have a Government Gateway login, sign in to your Personal Tax Account at gov.uk and use the 'tell HMRC about a change' section. The change is reflected within a few days and your tax code letter, payslip and P60 will all use your new name.
By post
Write to HMRC at Pay As You Earn and Self Assessment, HM Revenue & Customs, BX9 1AS. Include your National Insurance number, your old and new full name, your date of marriage and your address. You do not need to send the marriage certificate.
What changes automatically
- Your National Insurance record (your number stays the same)
- Your State Pension forecast
- Any Child Benefit, Universal Credit or Tax Credits you receive
- Your Self Assessment record
Marriage Allowance — worth checking
If one of you earns under the Personal Allowance and the other is a basic-rate taxpayer, you can transfer £1,260 of allowance to your spouse and save up to £252 a year. Apply on gov.uk under 'Marriage Allowance'.