HM Revenue and Customs (HMRC) has reminded UK households that a fixed £100 late filing penalty applies to Self Assessment tax returns not submitted by the deadline, even if no tax is owed. The tax office is encouraging people to begin their returns well ahead of the January 31, 2027, online filing deadline.
For paper returns, the deadline is 11.59pm on October 31, 2026, which is now just weeks away. Regardless of filing method, the deadline to submit the tax bill and pay any tax owed for the tax year is 11.59pm on January 31, giving households several months to plan and budget.
Early filing reduces stress
HMRC says more than a quarter (26%) of people experience anxiety when tax or financial deadlines approach. Preparing early can help minimise this stress and ensure tax returns are accurate, so individuals are not paying more tax than necessary.
Customers signed up to Making Tax Digital for Income Tax still need to submit their Self Assessment return and pay any tax owed by January 31, 2027. Self Assessment customers with a PAYE income can file online by 11.59pm on December 30 and have any tax owed collected via their tax code, with early filing allowing more time to explore payment options if needed.
Criteria for filing a return
A tax return must be sent to HMRC if, in the last tax year from April 6 to April 5, any of the following applied: self-employment as a sole trader earning more than £1,000 (before tax relief), being a partner in a business partnership, having to pay Capital Gains Tax on a sold or disposed asset that increased in value, having to pay the High Income Child Benefit Charge not paid through PAYE, or being an off-payroll worker repaying a student or postgraduate loan.
Returns may also be needed for untaxed income such as rent from property, tips and commission, savings interest, dividends, or foreign income. Those unsure whether they need to file for the 2025 to 2026 tax year can use the Self Assessment checker tool on GOV.UK, where they can also register or notify HMRC if they no longer need to complete a return.
Penalties for late filing
Failure to submit the return and pay any tax owed by January 31 results in a fixed £100 late filing penalty, even if no tax is due. After three months, an additional penalty of £10 per day applies, up to a maximum of £900. After six months, a further penalty of 5% of the tax due, or £300 (whichever is higher), is added. After 12 months, another 5% or £300 is added, and interest is charged on unpaid tax.
HMRC added: “Check the filing deadlines. The deadline for sending a paper return is before the deadline for an online return. You can send your return any time after 5 April. Sending it earlier means you: find out what you owe, can budget - if you want to make weekly or monthly payments, have time to pay your bill by 31 January, can set up a payment plan, if you do not think you can pay on time.”
