Changing your name on National Insurance means updating the name HMRC and the DWP hold against your number. The number itself never changes. There is no fee, your signed deed poll is the only proof you need, and what you actually do depends on whether you are employed or self-employed. For most people it means doing nothing with HMRC at all.
Your NI number is yours for life. It stays the same when you change your name, marry, divorce, or get a Gender Recognition Certificate; only the name attached to it needs updating. That still matters, because the record is used for right-to-work checks, benefit claims, and your State Pension forecast.
How to change your name on National Insurance
If you are employed, you do not need to contact HMRC yourself. Give your employer a copy of your deed poll. They update payroll, and the new name reaches HMRC automatically through the Real Time Information system that runs with every pay run. Self-employed, filing a Self Assessment return, or not currently working? Change your name through your Personal Tax Account on the Government Gateway, or call HMRC on 0300 200 3300 with your deed poll to hand.
Do you get a new National Insurance card?
No. Physical National Insurance cards stopped being issued in 2011, so there is nothing to reissue. Your NI number is unchanged and you do not need a replacement document to prove it. If you want written confirmation of the number under your new name, HMRC can post you a letter on request, but for almost everything your deed poll alone is enough.
Can you change your NI name online?
Yes, if you are self-employed or manage your own tax. Sign in to your Personal Tax Account on the Government Gateway and update your details there; this covers National Insurance and Income Tax together. Claiming Universal Credit or other benefits? The DWP keeps its own record against your NI number, so update your name through your benefit account or contact the DWP separately.
How long does it take?
If you are employed, the change reaches HMRC at your next pay run, usually within a month. Online updates through your Personal Tax Account are recorded straight away. There is no deadline either. Your deed poll stays valid indefinitely, so you can update the record whenever it suits you.