HMRC deadline in two weeks that could result in £1,600 fine

HMRC is continuing to urge people to not miss a vital deadline taking place in just two days

Both parents and workers are being warned that they have just a few weeks left to meet an important HM Revenue and Customs (HMRC) deadline or risk facing fines of up to £1,600.

The tax body has previously stated that anyone required to complete a Self Assessment must settle their outstanding tax by no later than 11.59pm on 31 January 2026. This deadline specifically applies to those submitting an online tax return, as opposed to a paper one, which should have been filed by 31 October the previous year.

If you’ve missed the deadline for your paper returns, you’ll already be subject to late filing penalties. You’re obliged to send a Self Assessment tax return if you were categorised as a self-employed ‘sole trader’ earning more than £1,000 in the last tax year, needed to pay Capital Gains Tax when selling or disposing of something that increased in value, or were a partner in a business partnership.

You may also need to submit a return if you had to pay the High Income Child Benefit Charge and don’t pay it through PAYE, or have untaxed income, which can include foreign income, tips and commissions, and rental income from property. You can check whether you need to send a tax return here.

With numerous methods available to settle your tax bill, HMRC is pushing people towards using the HMRC app, which handily sends payment reminders too. Myrtle Lloyd, HMRC’s Chief Customer Officer, said: “The Self Assessment deadline is less than one month away, and thousands of people have already paid their tax bill via the HMRC app.

“It is quick and easy to do, and you can also see your payment history. Search ‘download the HMRC app’ on GOV.UK to access the app and make your Self Assessment payment.”

A full list of payment options for tax returns can be found on GOV.UK here.

Penalties for missing the self-assessment deadline

HMRC rules make clear it can slap financial penalties on anyone filing late tax returns. It kicks off with a flat £100 charge, which can balloon rapidly if left unpaid.

Miss the deadline by three months and you’ll face daily penalties of £10, capping at £900. Six months down the line, this jumps to either 5% of the tax owed or £300 – whichever hits harder.

After a full year, another 5% or £300 charge lands, again whichever stings more. HMRC emphasises these penalties are completely avoidable by simply getting your Self Assessment tax return in on time.

Furthermore, those who fail to pay their tax on time will initially be slapped with a 5% charge of the unpaid tax 30 days after the due date. This penalty will then ratchet up by an additional 5% if the payment is six months and 12 months late, respectively.

HMRC also highlights that interest will be levied on any outstanding tax owed.

What if you receive a penalty

If you’re stung with a penalty by HMRC for either a tardy tax return or a late payment, you might be able to dodge paying it if you challenge the decision. According to HMRC guidelines, one valid reason for contesting the penalty is if you have a ‘reasonable excuse’.

Typically, you have 30 days from the date the penalty is issued to get in touch with HMRC and formally lodge an appeal. If a deadline was missed, you’ll need to provide a reason for the delay.

The process for filing an appeal will vary significantly depending on the type of tax you pay and whether you’re employed or self-employed. You can find full details here.