Self-assessment deadlines 2023-24

The deadline for submitting paper self-assessment tax returns for the 2023-24 tax year is 31 October 2024. If the return is submitted late, a £100 penalty will be imposed, regardless of whether there is a tax liability or if any owed tax is fully paid by 31 January 2025.

We recommend that taxpayers still using paper returns consider switching to electronic submission, which offers an additional three months (until 31 January 2025) to file their self-assessment tax return.

Taxpayers with certain underpayments in the 2023-24 tax year can elect to have this amount collected via their tax code (in 2025-26), provided they are in employment or in receipt of a UK-based pension. The coding applies to certain debts and the amount of debt that can be coded out ranges from £3,000 to £17,000 based on a graduated scale. The maximum coding out allowance applies to taxpayers with earnings exceeding £90,000.

Daily penalties of £10 per day will also take effect if the tax return is still outstanding three months after the filing date up to a maximum of £900. If the return still remains outstanding further higher penalties will be charged from six months and twelve months late.

You must inform HMRC by 5 October 2024 if you need to complete a tax return for the 2023-24 tax year and have not done so before.