> ## Knowledge Base Index
> Fetch the complete knowledge base index at: https://clipper.crisp.help/sitemap.xml
> Use this file to discover available pages before exploring further.
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# Applying for a UTR number for self-assessment

Should you wish to engage on a self-employed basis, you will need to register with HMRC for self-assessment. This process is essentially you self-declaring to HMRC, that you will be engaging this way.

In doing so, HMRC will issue you a a 'Unique Tax Reference' (UTR) number. This is your unique code that you will use in correspondence with HMRC as well as when you submit your self-assessment tax return.

You can register on the government website here: [https://www.gov.uk/register-for-self-assessment](https://www.gov.uk/register-for-self-assessment)

You must register for Self Assessment by 5 October if you need to complete a Self Assessment tax return and have not sent one before. You could be fined if you do not.

Should you be operating in the construction industry, you may also need to register for the Construction Industry Scheme (CIS). Our [article](/en/article/registering-for-cis-construction-industry-scheme-1vnb0jz/) explains how you can do this.