Register a partner for Self Assessment and Class 2 National Insurance
Register for Self Assessment and Class 2 National Insurance when you've joined a partnership using form SA401.
You can register as a partner for Self Assessment and Class 2 National Insurance contributions using the online service. If you’re unable to use the online services, you can register by sending a postal form to HMRC.
Register online
You’ll need a Government Gateway user ID and password. If you do not have a user ID you can create one when you register.
Register by post
If you cannot register online, you can register by post.
You can either:
- fill in an online version of the form, then print it
- fill in the PDF version of the form on-screen, then print it
- print the PDF version of the form, then fill it in
You’ll then need to send your completed form to HMRC.
Complete an online version of the form
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Get all of your information together before you start. You will fill this form in online and you cannot save your progress.
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Register using the online version of the ‘registering a partner for Self Assessment and Class 2 NICs (SA401)’ form.
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Print and post it to HMRC, using the postal address shown on the form.
If the form does not open, contact online services support for more help.
This file may not be suitable if you use assistive technology (such as a screen reader). If you need a more accessible format, email different.format@hmrc.gov.uk and tell us what format you need. It will help if you tell us what assistive technology you use. Read the accessibility statement for HMRC forms.
Complete the PDF version of the form
You can either:
- print the form and fill it in
- complete the form on-screen, then print it
You’ll then need to post your completed form to HMRC, using the postal address shown on the form.
To complete the form on-screen you need to:
- Download and save the form on your computer.
- Open it using the latest free version of Adobe Reader.
- Complete it on-screen.
The form may not work if you try to open it in your internet browser. If the form does not open, contact online services support for more help.
After you’ve registered
We’ll usually contact you within 21 days of receiving your form but may take longer during busy periods.
If you registered online, you may be able to get your Unique Taxpayer Reference (UTR) sooner using the HMRC App or your personal tax account.
If we have not contacted you after 3 weeks, you can check when you can expect a reply.
Related forms and guidance
Authorise a tax agent (64-8)
Use this form to tell HMRC that you give authorisation for someone to act on your behalf for individual or business tax affairs.