'Tis the season to file a tax returnTax self-assessment deadline is 31 January

24 December 2013

Christmas pudding

The deadline for filing your tax return online is fast approaching - you have to get it in by the end of January or face a £100 fine. And surprisingly Christmas Day is a popular time to get the job done.

If you complete your return on Christmas Day, you'll be joining hundreds of others doing the same thing. Last year 1,548 people filed  on Christmas Day, and 4,685 on Boxing Day, according to figures from HMRC.

New Year's Eve saw 27,161 submit an online return, followed by 12,007 on New Year's Day. A huge number leave it to the very last minute, as HMRC report that 578,000 people did it on the final day last year.

Go further: The Which? tax calculator- check your likely tax bill before you begin

Self-assessment tax

Around 10m people make a self-assessment tax return. The vast majority (80%) do so online, rather than making a paper return. One of the main reasons for this is because the online deadline is 31 January- three months later than the 31 October deadline for paper tax returns.

Those required to make a self-assessment tax return include those who are:

  • business partners, directors of limited companies or self-employed
  • employees or pensioners with an income of £100,000 or more
  • investors with pre-tax income of £10,000 or more
  • 'names' at Lloyd's
  • ministers of religion
  • trustees or representatives of someone who's died.

You may also be sent a tax return by HMRC if:

  • you have untaxed income 
  • you make capital gains above the annual exempt amount
  • you were required to make a return last year
  • you are a pensioner who receives age-related allowance 

Self-assessment tax deadlines

Making an online tax return is a similar process to filling in a paper form (SA100) but you need to prepare in advance, rather than leaving things too late.

Specifically, you need to register to use HMRC online services and set up an online account. This can take over a week as they need to send you an activation code by post.

Once you are set up, you'll need your ten-digit 'unique taxpayer reference' (UTR) and National insurance number. 

Self-assessment tax penalties 

If you miss the 31 January deadline for making a tax return, there is an automatic £100 penalty, even if you have no tax to pay. HMRC accepts very few excuses for late returns and fines escalate the longer you leave it, so it really is worth submitting a return as quickly as possible. 

More on this... 

Self-assessment- a guide for anyone submitting a tax return

Self-assessment online- a step-by-step guide to filing online

The Which? tax calculator- check your likely tax bill before you begin