More than 5.6 million people still need to file their self assessment tax return, with less than a month to go before the 31 January deadline, according to figures from HM Revenue & Customs.
While millions remain yet to complete their return for the 2024-25 tax year, thousands of taxpayers chose to start the new year with their finances in order.
HMRC said 54,053 people submitted their return on New Year’s Eve and New Year’s Day, opting to deal with their tax affairs rather than traditional celebrations.
In the final hour of 2025 alone, 342 people filed their return, while almost 20,000 submitted theirs on New Year’s Day, foregoing a winter walk or a day in front of the television. The busiest filing window across the two days was between 11am and midday on 31 December, when 3,927 people completed their return.
Overall, more than 6.36 million taxpayers have already submitted their self assessment, leaving about 5.65 million still to do so. Anyone who misses the 31 January deadline faces an automatic £100 late filing penalty, even if there is no tax to pay.
Myrtle Lloyd, HMRC’s chief customer officer, urged those who have yet to start to act quickly. “New Year is a great time to start afresh,” she said. “What better way than to ensure your tax affairs are in order for another year. If you have yet to start, the clock is ticking.”
HMRC said a wide range of online support is available via GOV.UK, allowing people to start their return, save progress and return to it as often as needed before submission. Although the tax bill does not need to be paid immediately after filing, payment must be made by 31 January.
The department said the simplest way to pay is through the HMRC app, which also allows users to set up reminders so they do not miss payment deadlines. Alternative payment options are also available.
Those unable to meet the deadline are advised to contact HMRC before 31 January. The tax authority said it would treat people with reasonable excuses fairly.
Penalties increase the longer a return remains outstanding.
After three months, daily fines of £10 apply for up to 90 days. Further penalties are added after six and 12 months, alongside interest on any unpaid tax.
Some taxpayers who currently complete a self assessment solely to pay the high income child benefit charge can opt to move to a new PAYE digital service, allowing the charge to be collected through their tax code instead. Eligible customers must notify HMRC before the filing deadline.
HMRC also warned that people completing self assessment are at increased risk of scams and should never share login details, including with tax agents. Guidance on avoiding fraud is available on GOV.UK.
