HMRC is urging the millions of people who are still yet to file their tax return to “act now” or risk facing £100 penalty. The warning comes as the deadline to complete the Self Assessment fast approaches on January 31.

HM Revenue and Customs (HMRC) is expecting more than 12.1 million tax returns to be filed for the 2022 to 2023 tax year along with any payment that is owed.

To date, more than 8.3 million online returns have already been received. This leaves around 3.8 million people to submit their forms.

Myrtle Lloyd, HMRC’s director general for customer services, said: “If you are a Self Assessment taxpayer, now is the time to take action and get your return done. People can familiarise themselves with the process by checking out HMRC’s online resources on GOV.UK.

“Once a tax return is submitted, it’s easy to find out what’s owed and to pay online or using the app. Just search ‘pay my Self Assessment’ on GOV.UK to find out more.”

People can pay Self Assessment tax bills online or using the HMRC app. A full list of payment options can be found on the Government website.

How to check if you need to complete a tax return

HMRC has an online tool that people can use to check if they need to complete a tax return.

For support on how to fill it out, people also have access to a range of YouTube videos. People can also find out where their refund is by using the where’s my reply tool.

Before picking up the phone to HMRC for Self Assessment help, the tax body has urged people to check for the answer online first.

It said: “It is much quicker, and the most common queries can be answered within a couple of minutes.”

Anyone who thinks they no longer need to complete a Self Assessment tax return for the 2022 to 2023 tax year is advised to let HMRC know. This means it will be able to issue a withdrawal notice – before the deadline on January 31, 2024, to avoid any penalties.

For anyone unable to pay in full, HMRC said it aims to help find an affordable way for people to pay the tax they owe.

For example, if a person owes less than £30,000, they may be able to set up a Time to Pay arrangement and can find out how to do this online without speaking to HMRC.

When completing a return, people are urged to ensure bank account details are included. This ensures that if HMRC needs to issue a repayment, it can be done quickly and securely without the need for issuing a cheque.

What are the penalties for missing the Self Assessment deadline?

According to HMRC, the penalties for late tax returns are:

• 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 three months, additional daily penalties of £10 per day, up to a maximum of £900
• After six months, a further penalty of five percent of the tax due or £300, whichever is greater
• After 12 months, another five percent or £300 charge, whichever is greater.

HMRC noted that it will consider a customer’s reasons for not being able to meet the deadline. Those who provide a reasonable excuse may avoid a penalty.