The SA1 form is the form that you need to use to register for a Self Assessment tax return with HMRC.
You have to register for Self Assessment if:
You can download the SA1 on HMRC’s website, if you want to register by post.
However, you can also register for Self Assessment online, in which case you don’t need to worry about this form. The link is on the same HMRC page.
Once you’ve registered for Self Assessment, you’ll receive a Unique Taxpayer Reference number – also by post. You’ll need your Unique Taxpayer Reference number to file your tax return via your HMRC Personal Tax Record.
Self Assessment is the process by which you pay the taxes you owe to HMRC on untaxed income. If you work full-time as an employee, you pay your taxes directly from your salary. This method is called Pay As You Earn (PAYE). But when you’re self-employed, you earn money gross i.e. tax is not deducted from it. This means that you have to declare your earnings to HMRC yourself and do a tax return by the 31st January following the end of the relevant tax year. For more information about completing a Self Assessment tax return, see our handy glossary page or contact one of our experts today!
When you register for Self Assessment with the SA1 form, you will be given a Unique Taxpayer Reference number by HMRC which you will use to identify your records.
The deadline for registration is 5th October following the end of the relevant tax year. If you fail to register by the deadline you will be faced with a penalty fine.