As of the 23rd October 2025, there’s officially only 100 days left until your Self Assessment needs to be submitted. For digital applicants, by the 31st January 2026, you’ll need to have fully submitted the Self Assessment form and paid any tax owed. Note: for paper tax returns, the deadline is 31st October 2025. Failure to meet the deadline can lead to financial penalties.
HMRC are today calling for business owners and self-employed individuals to start thinking about the Self Assessment deadline if they haven’t already submitted. With only 100 days to go until digital assessments are due, now is the best time to gather all the information you need to submit the form, and to make sure you have the money ready to pay the tax you owe in time.
As an SME owner you might need to submit a Self Assessment yourself, or you might hire or work with individuals who do, so being aware of the upcoming deadline is important. Read on to find out how you can prepare yourself or your workers for the deadline to make sure it runs smoothly.
What tax year does the next deadline cover?
You’ll need to submit information about the 2024-2025 tax year by the 31st January 2026 (digital applicants only). That means everything you earned from 6 April 2024 to 5 April 2025 must be considered and included in the assessment.
Why should I file my Self Assessment early?
HMRC have today announced that more than 3.5 million people have already submitted their assessment, but are encouraging those who haven’t to consider doing it sooner rather than later. In the 2023 to 2024 tax year, more than 11.5 million people filed their Self Assessment early, so the numbers suggest there are plenty more assessments to be submitted.
One thing to remember is that the Self Assessment system allows for you to dip in and out as required. Filing your self assessment (or asking your accountant to do it on your behalf) can be time consuming and you might not have all the info you need to hand. That’s OK. You can start the assessment now, and come back to it to edit the information and fill in any blanks as many times as you like before you hit submit.
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 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.
Do I need to submit a Self Assessment?
Unsure if you need to submit an assessment? Thankfully you can use the Self Assessment checker which will tell you if you need to submit a Self Assessment tax return or not.
What information do I need to file a tax return?
If this is your first time submitting a Self Assessment or you simply need a reminder, here’s pretty much everything you’ll need to hand to get started:
- Your Unique Taxpayer Reference (UTR) number – this is ten digits and can be found on most correspondence from HMRC, including your SA250, welcome letter, and more
- National Insurance Number
- Information about untaxed income from 06/04/2024 to 05/04/2025 – this includes money earned from self-employment, side hustles, dividends, interest, and more
- Information about expenses related to your self-employment – these expenses are taken from your total untaxed income to determine how much taxable income you have – so it’s in your best interest to be as thorough and accurate as possible here to make sure you’re only paying what you owe
- Anything that might allow for some form of tax relief including charity and pension contributions
- Your payslips or P60 showing income you’ve already paid tax on – if you work a full-time job and are paid via the PAYE system as standard, this income still needs to be considered when filing your Self Assessment as the total amount you earn in a year needs to be considered to determine your tax rates and exactly how much tax you owe
Next Steps For SME Owners
Need to file a Self Assessment? Or work closely with people that do? It’s time to get prepared to send. By filing sooner rather than later, you put yourself in the best position to avoid financial penalties, understand what you owe ahead of time, and give yourself time to get the money together to pay what you owe.
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