The countdown begins: Self Assessment deadline is 100 days away
Source: gov.uk (2025-10-23)

Self Assessment customers reminded to file their tax return with 100 days to go to the deadline.

- Self Assessment customers have 100 days to file their tax return and pay any tax owed before the 31 January deadline.
- 3.5 million people have already submitted their tax return for the 2024 to 2025 tax year.
- Customers are urged to file their tax return early, so they know how much tax needs paying by 31 January.
More than 3.5 million people have already filed their Self Assessment tax return for the 2024 to 2025 tax year and with 100 days to the 31 January 2026 deadline, HM Revenue and Customs (HMRC) is reminding those yet to file to do it early.

Those who start their return early can go back to it as many times as they need to before submitting it. Filing early means they also know how much tax is owed sooner and can prepare to pay their bill by the deadline.

Last year, more than 97% of tax returns were filed online. People can complete their tax return (https://www.gov.uk/log-in-file-self-assessment-tax-return) for the 2024 to 2025 tax year on GOV.UK where there is also access to a range of guidance (https://www.gov.uk/government/collections/get-help-filling-in-your-self-assessment-tax-return) to help them prepare and file their return.

Myrtle Lloyd, HMRC’s Chief Customer Officer, said:

With 100 days to the Self Assessment deadline, now is the time to get started. Completing your return now means you know you how much tax you need to pay ahead of the deadline. We are here to help with lots of help and advice, just search ‘file a tax return’ on GOV.UK to find out more.

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 (https://www.gov.uk/check-if-you-need-tax-return) 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 (https://www.gov.uk/guidance/work-out-your-capital-gains-tax-adjustment-for-the-2024-to-2025-tax-year) on GOV.UK.

The new High Income Child Benefit Charge (HICBC) PAYE digital service (https://www.gov.uk/child-benefit-tax-charge/pay-tax-charge-paye) 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 (https://www.gov.uk/topic/dealing-with-hmrc/phishing-scams) is available on GOV.UK.

Further Information

More information about Self Assessment (https://www.gov.uk/self-assessment-tax-returns).

The deadline for paper tax returns for the 2024 to 2025 tax year is 31 October 2025. Online filers have until 31 January 2026. More than 11.5 million people filed their tax return for the 2023 to 2024 tax year by the deadline.

Sole traders and landlords with a turnover above £50,000 will be required to use Making Tax Digital (MTD) for Income Tax (https://makingtaxdigital.campaign.gov.uk/) 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 (https://www.gov.uk/guidance/sign-up-your-business-for-making-tax-digital-for-income-tax) on GOV.UK to familiarise themselves with the new service and start preparing now. Agents can also register their clients (https://www.gov.uk/guidance/sign-up-your-client-for-making-tax-digital-for-income-tax) 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 (https://www.gov.uk/guidance/work-out-your-capital-gains-tax-adjustment-for-the-2024-to-2025-tax-year) 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.