Self Assessment Tax Returns

A Self Assessment is a type of tax return used to tell HMRC about income that you’ve received, but not yet paid any tax on.

Do I need to complete a Self Assessment tax return?

The good news it that not everyone needs to submit a Self Assessment tax return (sometimes known as an SATR). You can check if you need to send an SATR using HMRC’s online tool. There are different types of tax returns for other kinds of businesses; a limited company must submit a company tax return.

Self Assessment is usually a requirement for people who work for themselves in business, such as sole traders, partners, and directors of limited companies. In some cases, a separate Self Assessment tax return is also needed for the business itself. For example, partnerships submit returns which deal with the business, and individual partners each submit their own which deals with their income from the business.

How do I tell HMRC that I need to send a Self Assessment tax return?

You’ll need to register for Self Assessment before you can send a tax return. The process that you use to register depends on why you need to submit one.

Self-employed sole traders can register for Self Assessment online.
Partners must register using an SA401 form.
The nominated partner must also register the partnership in its own right, with an SA400 form.
If you’re not self-employed, but need to register for Self Assessment for a different reason (such as to declare income you make through property, or because you’re the director of a limited company), then you can register using an SA1 form.

The deadline to register for Self Assessment is 5^th October.

What happens after I register for Self Assessment?

Once you register, HMRC will send out your Unique Taxpayer Reference (UTR), which you’ll need each time you submit your tax return. If you’re a partner in a partnership you’ll receive your own separate UTR number, as well as one for the partnership itself, so be careful not to mix them up!

It can take up to two weeks (or three if you live abroad) to receive your UTR number.

How do I submit a Self Assessment tax return?

Most people can submit their Self Assessment return online, though there are exceptions to this, including partnerships, which submit their return by post. Partners can still submit their individual returns online, though.

You can use an accountant to calculate and submit a Self Assessment tax return on your behalf.

Is there a deadline for submitting my Self Assessment tax return?

The Self Assessment deadline depends on how you plan to submit your tax return:

Paper tax returns must be submitted by 31^st October, in the same calendar year that the tax year ended. E.g., submit your 2021/22 tax return by post by 31^st October 2022.
Online tax returns must be submitted by 31^st January, in the calendar year after the tax year ended. E.g., submit your 2021/22 tax return online by 31^st January 2023.