Skip to Content

What is an SA1 Form?

Find out what an SA1 form from HMRC is, when it should be used as well as where to find it online and tips on filling it out.

Friendly Disclaimer: Whilst I am an accountant, I’m not your accountant. The information in this article is legally correct but it is for guidance and information purposes only. Everyone’s situation is different and unique so you’ll need to use your own best judgement when applying the advice that I give to your situation. If you are unsure or have a question be sure to contact a qualified professional because mistakes can result in penalties.

1. What is an SA1 Form

An SA1 is a form issued by HMRC for individuals who need to register for self-assessment because they need to fill in a tax return, with the exception of those registering as self-employed. Reasons individuals need to fill out an SA1 form include:

2. Where to Find an SA1 Form Online

The easiest way to fill in a SA1 form is to go online to the .GOV website here. To fill in the form, you’ll need to have a personal tax account but you’ll be prompted to either set one up or login to your existing one before you can access the form (here’s what to do if you’ve lost your user ID or password).

3. How to Complete an SA1 Form

Registering with HMRC will be easier if you have the information you need to hand. Here’s what you’ll need:

  • Name
  • Date of Birth
  • UK Address
  • National Insurance Number
  • Telephone number
  • Email address

As part of completing the SA1 form, you’ll need to confirm your reason for registering for self-assessment and why you need to complete a tax return.

4. What Happens Next

HMRC’s guidance says the registration process takes 7 – 10 days to complete. However, there can be delays with this timescales. To get an up to date estimate of how long your application will take you can call HMRC on 0300 200 3310.

You’ll need to wait for two things:

  • An activation code to complete the setup of your HMRC Government Gateway account;
  • A UTR number that completes your successful registration.

From that point on, you’ll need to follow the rules of self assessment, which includes keeping business records, working out your own taxes and filling in a tax return (also referred to by HMRC as an SA100 form) online by 31 January each year. It’ll help to update your diary with all the tax year dates so you can stay on top of your deadlines.