A self assessment tax return form is used by individuals who have untaxed earnings.  They need to declare this income in the correct boxes.  They must also work out how much tax they have to pay on their earnings and show this figure on the form.  Self assessment is the way HMRC keep track of individuals earnings and taxes.

What is a Self Assessment Tax Return Form

In years gone by the self assessment tax return was a paper form which was posted to HMRC. This was quite time consuming and meaning individuals needed to make sure that HMRC sent them all the right sections in advance of filing deadlines. Thankfully it is now required to be completed online apart from in exceptional circumstances.

Where to find your Self Assessment Tax Return Form Online

You will have set up a online account as part of letting HMRC know that you need to fill out a a self assessment tax return form.  Log into your online account and you will find details of self assessment once in.

What are the Sections of a Self Assessment Tax Return Form

A self assessment tax return form is made up of different sections – the main section and supplementary sections.

Main Section

This part includes your personal information as well as details of:

  • Pensions;
  • Interest;
  • Dividends;
  • Tax reliefs and allowances you wish to claim for;
  • Which supplementary sections you need to include.
Supplementary Sections

You only need to fill out and include the supplementary sections relevant to you.  The supplementary sections available are:

Here are two samples of the paper version of the self assessment tax return form.

Tax Return Sample

Self Employment Tax Return Section Sample

One tax self assessment return form covers one tax year and is due for filing by 31 January the following year.  A tax year runs from 6 April to 5 April.

Example – your self assessment tax return form for the tax year 6 April 2017 to 5 April 2018 is due for filing by 31 January 2019.

Which Sections of the Self Assessment Tax Return Form Should You Complete

You need to include ALL your income for the tax year on your tax return.  So you must include all the sections that are relevant to you.


Kim works full time in a PAYE job but also has a rental property and receives bank interest.  Kim needs to complete the following sections:

  • Employment – Kim needs to enter her gross salary for the year and any tax deducted;
  • Land and Property – Kim needs to enter details of rental income and allowable rental expenses;
  • Interest – Kim must enter the gross amount of bank interest received and tax deducted.
  • When You Need to Complete a Self Assessment Tax Return Form

If Kim completes her Tax Return online HMRC will calculate how much tax Kim needs to pay for the year based on her total earnings.  There will then be a deduction made for any tax she already paid for example the amount her employer deducted.

How to Complete a Self Assessment Tax Return Form

There’s nothing stopping you from completing your own self assessment tax return, if you feel confident to do so.  However you can also choose to use a professional accountant to complete it on your behalf.  If you do choose to engage with an accountant then make sure you ask these 5 Essential Questions Before You Hire an Accountant.

Anita is a Chartered Accountant, turned blogger and creator of the ever popular free Go Self Employed Email Mini Course, which has been completed by hundreds of attendees all over the UK. Using her 10 years experience in accounting, tax and operations for Small Businesses, Anita is on a mission to make finance simple for the self employed, so they can stop stressing about tax & finances and focus on building profitable businesses which will give them the lifestyle they dream of.