When to register for self assessment?
You must register for self-assessment with HMRC if you need to submit a tax return & you didn’t need to for the prior year. If you were self-employed as a sole trader and earned more than £1,000 (before taking off anything you can claim tax relief on), then you will need to file a tax return.
So what’s the registration deadline?
The deadline for registering for Self Assessment is the 5th October that follows the end of the tax year that the Self Assessment tax return you’re filing relates to.
For example, if the tax return relates to the tax year starting 6th April 2023 and ending 5th April 2024, you should register for Self Assessment by 5th October 2024. You can still register after the deadline, but you might be fined.
If you registered for Self Assessment and filed a tax return last year, you don’t need to re-register in order to submit this year’s return.
How do I register for self-assessment?
If you already have a Government Gateway account, then you can register by signing into it & adding Self-assessment to your list of services.
If you don’t have a Government Gateway account, then you can create 1 by following this link: 'Create a Government Gateway account'. Click ‘Sign in’, then afterwards click on ‘Create sign in details’.
You should receive a letter from HMRC with your Unique Taxpayer Reference (UTR) number within 10 working days. You should also receive a separate letter within seven working days with an activation code for your business tax account. You can retrieve a lost UTR number or get a new activation code from HMRC if you lose either of them after they arrive.
Once you’ve received your UTR number and activation code, you can log in to and activate your business tax account. Once you’ve done this, you should be able to add Self Assessment to your list of services and file your tax return.