GOV.UK
Register for Self Assessment
1. Overview
You need to register for Self Assessment if you have to send a tax return and didn’t send one last year.
How you do this depends on whether:
- you’re self-employed
- you need to send a return for any other reason
You can appoint someone to register and send your tax return for you, eg an accountant, friend or relative.
You register online even if you want to send a paper return.
When to register
Register by 5 October following the end of the tax year you need to send a tax return for. If you’re late, you won’t get a penalty as long as you pay your Self Assessment bill in full by the deadline.
The tax year is from 6 April to 5 April the following year.
It can take 20 working days (this is usually 4 weeks) to complete the registration process. Allow time so you can send your tax return by the deadline. This is 31 January, or 31 October (3 months earlier) for paper returns.