HMRC has reminded taxpayers to prepare for the upcoming self-assessment deadline, noting that payments and return submissions must be completed on time to avoid penalties and interest.

The UK’s HM Revenue & Customs (HMRC) reminded individual taxpayers that the deadline for the 2024–2025 self-assessment tax year is 31 January 2026. Tax payments are due by this date, while the filing deadline varies by method: online returns must be submitted by 31 January 2026, whereas paper returns are usually due by 31 October 2025.

This announcement was made on 23 October 2025.

More than 3.5 million people have already filed their Self Assessment tax return for the 2024 to 2025 tax year.

Anyone unsure if they need to fill in a tax return for the 2024 to 2025 tax year, can use the Self Assessment checker tool on GOV.UK where they can also register and notify HMRC if they no longer need to complete one.

People who have sold assets such as shares after 30 October 2024 need to be aware of changed rates of Capital Gains Tax for the disposal of assets when completing their Self Assessment tax return as it won’t automatically calculate the correct amount of Capital Gains Tax due. Instead, they may need to work out an adjustment to the tax automatically calculated using the adjustment calculator on GOV.UK.

The new High Income Child Benefit Charge (HICBC) PAYE digital service means thousands of Child Benefit claimants who are only in Self Assessment to pay HICBC can now opt out and can choose to pay the charge back through their tax code.

Eligible customers can call HMRC to de-register from Self Assessment before the filing deadline in a tax year. Where a tax return has already been sent, customers can choose to de-register from the following tax year. HMRC will then amend their tax code and they will be registered to pay HICBC through PAYE.

Customers do not need to include their 2025 Winter Fuel Payment, or Pension Age Winter Heating payment in Scotland, on their tax return for the 2024 to 2025 tax year as payments received in Autumn 2025 will be recovered in the 2025 to 2026 tax return, due by 31 January 2027.

Customers need to be aware of the risk of falling victim to scams and should never share their HMRC login details with anyone, including a tax agent, if they have one. HMRC scams advice is available on GOV.UK.

Sole traders and landlords with a turnover above GBP 50,000 will be required to use Making Tax Digital (MTD) for Income Tax from 6 April 2026 and be required to submit quarterly summaries of their income and expenses to HMRC. HMRC is urging eligible customers to sign up to a testing programme on GOV.UK to familiarise themselves with the new service and start preparing now. Agents can also register their clients via GOV.UK.

Capital Gains Tax rates for disposals of assets on or after 30 October 2024 have changed and the Self Assessment tax return will not automatically calculate at the new main rates for the 2024 to 2025 tax year. Taxpayers may need to work out an adjustment to the tax automatically calculated and can use the adjustment calculator on GOV.UK.

Customers can also use the HMRC app to find out how to register for Self Assessment, check their Unique Taxpayer Reference, get their National Insurance number and employment income and history and pay their tax bill.