How do I register for Self Assessment?

How do I register for Self Assessment? Register online on GOV.UK by 5 October after the end of the tax year you need to report. If you were new to Self Assessment in 2025-26, that date was 5 October 2026; register now if you missed it. Register as soon as you can. GOV.UK says that if you tell HMRC after 5 October 2026 you could get a penalty, and your 2025-26 return is still due online by 31 January 2027. GOV.UK says you must register as a sole trader if you earn more than £1,000 in a tax year, before taking off expenses. You can choose to register earlier. Yes. GOV.UK says that if you are already registered for Self Assessment for another reason, you need to register again as a sole trader. That also registers you for Class 2 National Insurance. Read the full answer, with every source, at rightotax.co.uk.