We know it comes round every year at the same time, but sometimes the very words ‘self-assessment tax return’ can have us burying our heads in the sand and procrastinating until the very last minute.

This might be the biggest of the most common tax return mistakes – ignoring your tax returns until they become so urgent that in your rush to get them filed you end up making more mistakes than you might have done before, and these mistakes can be costly.

To support you, we have put together an outline of the most common mistakes that people generally make when filling out their tax returns, so that you can get your tax affairs back into order and control, which will ultimately help you to reduce stress and anxiety every year.

What happens when you miss the deadline and file a late tax return?

The dates do not change year on year. If you are filing a paper tax return, it needs to be with the HMRC by 31 October. If you are filling out your tax return digitally, then that date is extended to 31 January.

Late filing is punitive. Even if you file just one day late, you can be charged £100. Beyond this, there is a sliding scale of fines. Up to three months late, you are charged £10 per day. Up to six months late is a further £300 or 5% of your due bill; (whichever is greatest. Finally, up to 12 months late is a further £300 again, or 5% of your bill.

So, you can soon calculate how filing a late tax return could end up costing you significant sums.

Withholding vital information – or making an honest mistake

You are legally obliged to declare all income to the HMRC. Assuming that you are not deliberately hiding income from the taxman, many people fall into the trap of not keeping proper financial records, which sets you up to make unwitting mistakes when submitting your self-assessment tax return.

Keeping good records will not only help you avoid leaving out vital information, but it will also make the whole self-assessment process that much faster and easier for you and your accountant.

The HMRC takes a dim view on missing information – even if it is a genuine mistake and will charge a penalty. That penalty will be commensurate with the mistake, and if it is found to be due to a lack of reasonable care, then it may be up to 30 percent on top of the additional tax due.

However, if it is found that the mistake was deliberate and designed to conceal, then the penalty could be anything up to 100 percent on top of the additional tax due.

Create a paper trail

The more you can create that paper trail – both physical and digital – of every aspect of your financial life, the happier the HMRC will be. The taxman deal in black and whites at all times but can also the greys that lie beyond. If your tax is wrong, and there is no proof to back up your claims, then you are opening yourself up to a time-consuming and messy investigation.

You also need to keep your records for at least two years – longer if you are running a business.

The devil’s in the details

When you sit down to fill in your online tax return, make sure that you have as much information as you can to hand. As you fill it out, there may be things that you do not know, or are not sure about. Do not leave these blank. You can save your online tax return and return to it as many times as you need before submitting it. If a box or section is asking to be completed, then make sure that you complete it with the correct and relevant information.

Do double- and triple-check your numbers. The online forms do carry out a lot of the calculations for you – which makes it even more important for you to be accurate and specific with your information. The more complicated your tax affairs, the more you are advised to seek the help of a professional when filing your tax returns. Not only will they ensure you avoid any mistakes and calculations, but they will also know regulations that might enable you to make tax savings that you may not have previously known about.

Even simple mistakes can occur, like not signing in the right place or getting your numbers wrong.

Is the taxman ever wrong?

Knowing when to fill out your tax return, and how to fill it, are the responsibility of the individual. If you make a mistake, the onus is on you to rectify that mistake.

If you are confident that you have done everything in your power to demonstrate that your tax return is correct, and you believe that the taxman has made a mistake, then you are within your rights to report it, but be prepared to fight your corner.

Tax Refunds R Us can ease the process for all your tax return and self-assessment issues, filing paperwork, calculating payments, and claiming for refunds if applicable. If you would like help with your tax returns, please do not hesitate to contact us.