This tax season, the self assessment deadline is a critical date for anyone with untaxed income in the UK. Whether you’re a seasoned entrepreneur or just starting your first side hustle, understanding this deadline and the potential penalties for missing it is crucial. This comprehensive guide provides all the necessary details on the UK self assessment deadlines, including how to complete tax returns, covering income tax, and National Insurance.
Understanding the Self Assessment Deadline
The self assessment deadline in the UK is typically 31 January each year. This is when your online self assessment tax return for the previous tax year (6 April to 5 April) is due.
This is also when any tax owed should be paid. For example, the 2023/24 tax year ended on 5 April 2024.
The resulting self assessment deadline to file your return and pay any outstanding tax was 31 January 2025. There’s also a 31 October deadline for those opting for the paper tax return method.
Who Needs to File a Self Assessment Tax Return?
This mostly applies to self-employed individuals, or sole traders, who must report their earnings, even profits over £1,000. This differs from those with employment where tax is deducted at source through the Pay As You Earn (PAYE) system. Some situations can require additional filing, impacting your tax code and potentially leading to a tax refund.
For example, landlords receiving rental income often need to file, even if their primary job uses PAYE. Other situations requiring filing include significant income from savings, investments, or dividends above your personal allowance, as these fall under capital gains tax.
It’s important to understand these rules to avoid issues with HMRC and potential penalties. Understanding the nuances of PAYE tax, income tax, and National Insurance contributions is essential for accurate filing.
Key Dates for the Self Assessment Process
While 31 January and 31 October are important, they aren’t the only important dates in the self assessment journey. Here are some other key deadlines for assessment tax returns and payments:
| Date | Action |
|---|---|
| 5 October | Register for self assessment (if you haven’t filed before or already told HMRC you’ll need to file). You can register online through the Gov.UK registration form. Other options include online services with a Government Gateway ID, the SA1 form (for those not self-employed), and the CWF1 form (printable after completing digitally). For assistance, contact the self assessment helpline. |
| 31 October | Deadline for posting paper tax returns. Ensure you submit your form SA100 by this date. |
| 30 December | Inform HMRC if you are eligible for and prefer automatic tax collection from your wages and pension. This applies to those who have already paid tax. Check HMRC’s rules for more details. |
| 31 January | Deadline for submitting online tax returns via the Government Gateway or compatible software, outlined in gov.uk guidelines. This date also marks the due date for paying the total tax owed. Discuss payment plan options with HMRC if you owe under £30,000 and face challenges paying the full amount. |
| 31 July | Second payment deadline for those making payments on account. This is an important date for managing your cash flow. |
Penalties for Missing the Self Assessment Deadline
Missing the self assessment deadline can be costly. Initial penalties include a £100 fine from HMRC.
Greater penalties apply depending on how overdue your return is. Further penalties accrue if the tax owed remains unpaid after the deadline. Remember, this is on top of any interest incurred. You can consider submitting form SA370.
Appeals against penalties are possible if you have a reasonable excuse. Use the SA370 form to submit your appeal, providing all necessary supporting evidence to justify the delayed filing.
Payments on Account: A Closer Look
Those whose self assessment tax bill frequently exceeds £1,000 usually pay through payments on account. This involves two advance payments based on your previous year’s liability, spreading your tax payments more evenly.
The first instalment is due on 31 January. The second payment is due on 31 July. This system simplifies paying a large tax return payment.
It helps to budget for these payments throughout the year. Payments on account provide more predictability to the amount you owe.
Tools and Resources
Several resources can assist with tax reporting, including software tools for organizing expenses. Tools like self assessment worksheets can be very helpful for organising data. Even spreadsheet templates can prove useful for keeping records.
Making Tax Digital (MTD) will change future requirements. It will make using software even more important. However, currently these tools can still simplify tracking income and expenditures year-round, reducing stress at tax time.
MTD is expected to make paying tax, filing tax returns online, and claiming tax relief more efficient.
Helpful Guide: Read about how to file a self-assessment tax return in the UK
Conclusion
Navigating the UK’s self assessment deadline isn’t overly complicated. Understanding these key dates, penalties, and payments on account will clarify how the system works.
Utilising available tools, like those mentioned above, and seeking expert advice where necessary, can streamline the tax return process. Remember to make use of all resources available for making tax digital.
Planning and organization will help transform a potentially stressful task into a more manageable yearly duty.
How Sleek Can Help with Your Self Assessment and Tax Returns
Filing your Self Assessment tax return can be overwhelming, but Sleek is here to make it simple. Our expert team takes the stress out of the process by handling everything from accurate calculations to timely submissions. Whether you’re self-employed, a landlord, or have additional income to declare, we ensure your tax return is error-free and compliant with HMRC regulations.
With transparent pricing and a dedicated support team, we’ll guide you every step of the way—saving you time and helping you avoid unnecessary penalties. Let Sleek simplify your Self Assessment today.
FAQs about how to determine IR35 status
What is the UK Self Assessment deadline?
The deadline for online submissions is 31 January following the end of the tax year. Paper returns must be filed by 31 October.
Who needs to file a Self Assessment tax return?
You may need to file if you’re self-employed, a landlord, earn income over £100,000, or have untaxed income, such as from dividends or overseas earnings.
What happens if I miss the Self Assessment deadline?
Missing the deadline can result in an initial £100 penalty, with additional charges for prolonged delays or unpaid tax.
Can I amend my tax return after submitting it?
Yes, you can make changes to your tax return within 12 months of the filing deadline.
What information do I need to complete my Self Assessment?
You’ll need your National Insurance number, Unique Taxpayer Reference (UTR), income records, expense details, and any other relevant financial documents.
What expenses can I claim on my Self Assessment?
You can claim business expenses like travel, office supplies, and professional fees. If you work from home, even just for a small period of your working time, you can claim back for a portion of some of your utilities. We can help you identify allowable expenses to maximize your deductions.
