Self-assessment tax return deadline is January 31 - here's what you need to know

Millions of people still need to fill in their self-assessment tax forms or risk a fine.

With the clock ticking down to the 11.59pm, January 31 deadline, HMRC believes about 5.4 million workers have yet to file their online returns.

Angela MacDonald, HMRC’s Director General for Customer Services, said: "We know that can be a worry, and not only when large sums are involved, so I would urge anyone who is expecting to find it difficult to pay their tax to get in touch with us as soon as possible.

"We will do everything we can to help and provide practical support."

So, who needs to file one, what do you need to do so and where can you go to get help?

Don't let your filing your tax return peck away at you. Credit: HMRC

Who needs to file a self-assessment form?

The last tax year started on 6 April 2018 and ended on 5 April 2019.

People need to complete a tax return if they:

  • or their partner received Child Benefit and either of them had an annual income of more than £50,000

  • received more than £2,500 in other untaxed income (for example, tips or commission, income from renting out a property, income from savings or investments)

  • are self-employed sole traders and earned more than £1,000

  • are a partner in a business partnership

  • are employees claiming expenses in excess of £2,500

  • have an annual income over £100,000

If you completed a Self Assessment tax return last year but didn’t have any tax to pay, you will still need to complete a 2018 to 2019 tax return unless the HMRC has written to tell you it's not required.

You can check here it you need to send a tax return.

The online tax return system. Credit: .

How do I file?

If you're a regular filer, you should be able to login to your self-assessment account using your Government Gateway or Gov.UK Verify details

However, if you've not filed online before, you better be quick as setting up an account can take more than two weeks.

Your 10-digit unique taxpayer reference (UTR) can take up to 10 days to arrive - and an activation code can take a further seven days.

Forgotten your login details?

If you've previously filed online but have forgotten your login details or mislaid them, then you can retrieve the Government Gateway details through this link.

If you have lost your UTR (although it should be on other correspondence from HMRC), you can phone the self-assessment helpline on 0300 200 3310.

When must you settle up - and how can you pay?

You have to make two payments on account every year unless your last self-assessment tax bill was less than £1,000 or you’ve already paid more than 80% of all the tax you owe, for example through your tax code or because your bank has already deducted interest on your savings.

Any money you owe for the 2018/19 tax year must be paid by midnight on January 31.

Many of those filing self-assessment forms must pay half of what's due for the 2019/2020 tax year - known as "payment on account" - and that's due by the end of July this year.

You can pay via bank transfer, debit card or cheque. You can also pay at yur bank or building society, if you have a paying in slip from HMRC.

What are the penalties for late filing or payment?

  • an initial £100 fixed penalty, which applies even if there is no tax to pay, or if the tax due is paid on time

  • after 3 months, additional daily penalties of £10 per day may be charged, up to a maximum of £900

  • after 6 months, a further penalty of 5% of the tax due or £300, whichever is greater

  • after 12 months, another 5% or £300 charge, whichever is greater

  • There are also additional penalties for paying late of 5% of the tax unpaid at 30 days, 6 months and 12 months. Interest will be charged on all late payments.

If you haven't got the money to pay your tax bill, contact HMRC as soon as possible.

Failure to get your assessment in on time or your bill paid on time will cost you more money - unless you have a strong excuse, such as a family emergency or sudden illness.

Here's some of the less believable excuses HMRC received last year: