Online Self-Assessment

Online Self-Assessment

How to complete your self-assessment tax return online.

For self-employed people, company directors and those receiving other sources of income, it's the time of the year to send your self-assessment tax return.

Self-assessment is the process used by HMRC to collect tax from individuals who may own a business or receive income outside of formal employment.

A tax return is a form which accounts for all income on individual received during the tax year, which runs from 6 April to 5 April.  This can be completed on paper or online.

While the fundamentals of self-assessment remain unchanged, more and more people are becoming self-employed.

Figures from the Office for National Statistics reveal the number of workers registered as self-employed at the end of August 2017 reached 4.86 million.  This us up 70,000 on the same time in 2016.

As self-employment is proving popular, many who have left employment will be coming into self-assessment for the very first time.  This article will go through the process of self-assessment and the steps to complete your tax return on time.


In order to send a tax return you first need to register for self-assessment with HMRC.  The deadline to register for the 2016/17 tax year was 5 Oct 2017.

You only need to do this once so if you have registered in the past you don't need to re-register each year.

You may need to complete a self-assessment tax return if you:

- are self-employed

- earned £2,500 or more in untaxed income (such as from rental property)

- earned £10,000 or more from savings or investments

- received profits from assets subject to capital gains tax

- were a company director

- received dividends of £10,000 or more

- received child benefit and you or your partner earns £50,000 or more

As a self-employed person you need to register for self-assessment as a sole trader.  You can do this online through the HMRC website.

Once you've registered with HMRC you will receive a letter within 10 days containing your 10 digit unique taxpayer reference (UTR) and an activation code to set up your online account.

If you're not self-employed and need to register for self-assessment, you must complete form SA1.

If you are in a partnership then you need to register as a partner.  You need to register both yourself and the business as a partnership if you are a 'nominated partner'.

Filing You Tax Return

Once registered, the next step with HMRC is to complete the tax return form and submit it.

There are two ways to complete your self-assessment tax return - downloading, printing and filling in SA100 paper form or filling it in online through the HMRC website.

The deadline for paper forms was 31 Oct 2017 but you have until 31 Jan 2018 to send you tax return online.

You'll need your UTR, user ID and password to sign in to our online account.

SA100 is the main tax return form for self-employed people.  This is used to record any income, capital gains and pensions and tax reliefs collected during the financial year.

There are various commercial software tools available that can submit parts of the tax return or you can use HMRC's free software.  Visit the HMRC website to see the services which are compatible.


There are four deadlines to keep in mind when completing your self-assessment tax return and paying tax to HMRC.  These are:

Self-Assessment Task Deadline
Registering 5 October
Submitting paper tax return 31 October (midnight)
Submitting online tax return 31 January (midnight)
Paying tax 31 January (midnight)


If you miss the self-assessment deadline, you could face a penalty charge.

If your return is up to 3 months late, you will receive a penalty of £100 and this could go up further if you leave it longer.

You can appeal against a penalty but this can only happen if your is a reasonable excuse.

The following circumstances may provide grounds for an appeal:

- if a partner or close relative has passed away prior to the deadline

- serious illness

- an emergency hospital stay

- unexpected delays in the post

- an IT failure (hardware or software) when preparing your tax return

- external causes (fire, flood or theft) which prevented you from completing a return

- issues with HMRC services

If you require help with self-assessment, get in touch with Elpizo Accountancy.