Completing your first Self Assessment - a step-by-step guide

  • By Josh Hall
  • 14 December 2010
Completing your first Self Assessment - a step-by-step guide

As the end of the year approaches, many first-time Self Assessment taxpayers will be starting to panic about filing their return.

Horror stories abound when it comes to Self Assessment. But, in reality, completing your tax return need not be too hellish an experience – provided that you have the necessary information to hand.

Get your records in order

Record-keeping is a vital (if dull) fact of life for every self-employed person. You have a range of legal obligations when it comes to record-keeping – but entirely apart from this, the Self Assessment process will be significantly easier if you have the relevant documents easily to hand, and organised in an effective way.

The documents you require will depend on the nature of your business. Regardless of your circumstances, though, you will definitely need all of your invoices, as well as receipts for any business expenditure for which you intend to claim.

You should seriously consider investing in some decent bookkeeping software, and using this to keep your records throughout the year. Then, come January, filling in your Self Assessment can be as simple as pressing a couple of buttons then copying the figures calculated by your software.

Decide on a format

You can file your Self Assessment tax return online or by post. HM Revenue and Customs are trying to encourage taxpayers to file online, and there is a range of benefits associated with this method of filing. Amongst other things, they will work out your tax bill for you, provided you meet the deadline.

If you are leaving your tax return to the last minute, you should understand that you need to register for the online service. HMRC will then send you an activation code by post – and this can take several days to arrive. So, if you intend to file online, you should make sure that you leave enough time to make up for the vagaries of the postal system.

Know the deadlines

There are several Self Assessment deadlines, and the one to which you must adhere will depend on how you choose to file.

January 31 is the date everyone knows, as it is the last possible date by which you must file. This is the online filing deadline; if you miss this deadline you will be fined £100.

If you intend to file on paper, you will need to make sure that your return reaches HMRC by midnight on 31 October. The only exception to this is if you received your notice to file after 31 July. In these cases your deadline will be 3 months following the date you received your return.

Finally, if you think you will owe less than £2,000 and you want your tax to be collected through the PAYE system, you must ensure that you file online by 30 December. HMRC will then try to adjust your tax code accordingly, but you should note that this is not always possible.

Ask for additional pages

The basic Self Assessment form is sufficient for most taxpayers. However, depending on your circumstances you may need to provide HMRC with additional information – and for this you will require additional pages.

Additional pages are particularly commonly required when the taxpayer is a trustee. In these cases you may need a range of pages including form SA900 and SA904. You should contact HMRC or your accountant if you think you will need to provide additional information.

Complete the form

As long as you have your records in order and you have any additional pages to hand, the process of actually completing the Self Assessment form is pretty easy.

If you are filling the form in on paper, extra guidance is available from HMRC to help you through the process. You should have received this with your tax return; if you did not, you can download it from the HMRC website. If you are filing online, you will notice green question marks by each input field. By clicking these icons you will launch a popup containing more information related to that question.

Check your working

Finally, it is vitally important that you check your figures before you file your return. There are potential penalties in store for those who provide incorrect information – and, apart from this, you could simply end up paying too much tax.

It is therefore vital that you check your figures thoroughly before clicking submit or sealing the envelope.

Completing your first Self Assessment can seem like a daunting prospect. But, provided that you have everything in order in advance, the reality should not be too taxing.

Read more about: Tax and finance