Self Assessment Deadlines and What You Need to Submit

If you are self-employed, a company director, or receive income outside of PAYE, completing a Self Assessment tax return is a key responsibility. Missing deadlines can result in penalties, so it’s important to understand both the submission dates and the information you’ll need to provide.

Key Self Assessment Deadlines

HMRC sets strict deadlines for Self Assessment each tax year:

• Registering for Self Assessment: If you’re filing for the first time, you must register by 5 October following the end of the tax year.
• Paper Tax Return Deadline: Paper returns must reach HMRC by 31 October.
• Online Tax Return Deadline: Online returns are due by 31 January after the end of the tax year. For example, for the 2023/24 tax year (ending 5 April 2024), the deadline is 31 January 2025.
• Tax Payment Deadline: Any tax you owe must also be paid by 31 January. If applicable, a second payment on account is due by 31 July.

Missing these dates can lead to late filing penalties and interest on unpaid tax.

What You Need to Submit

When completing your Self Assessment, you’ll need to provide accurate details of your income, expenses, and any allowances you are claiming. This may include:

• Employment income (if you receive a salary alongside self-employment)
• Self-employment income and expenses
• Dividend income from investments
• Rental income and related expenses for landlords
• Interest earned from savings or other investments
• Capital gains from selling assets such as shares or property
• Pension contributions and charitable donations that qualify for tax relief

Supporting records such as invoices, receipts, bank statements, and expense logs should be kept safe, as HMRC may request evidence.

Preparing in Advance

Leaving your tax return until the last minute can be stressful and increases the risk of errors. Preparing early gives you time to gather all necessary documents, check for missing information, and seek advice from your accountant if needed. It also helps you budget for any tax owed rather than facing an unexpected bill.

Final Thoughts

Understanding Self Assessment deadlines and requirements is vital for staying compliant and avoiding penalties. By preparing in advance and keeping clear records, you’ll find the process much smoother. Working with an accountant can also save time, reduce stress, and ensure your return is accurate and tax-efficient.