Questions and Answers
I can’t file my self-assessment tax return by 31st January, will I get a penalty?
I should have filed a 2024/25 self-assessment tax return, but I was not able to get it filed by 31st January 2026, will I get a penalty if I file it by the end of February 2026?
Last updated 12 Feb 2026 | First published 25 Jan 2022
By Helen Wood, CA 1 min read
Self-Assessment Tax Returns
The deadline for filing your 2024/25 self-assessment tax return and paying the tax due was 31st January 2026.
Late filing
If you submit your tax return after this date you will automatically receive a late filing penalty of £100.
If you submit your return within the next three months of the deadline, you will avoid the next wave of late filing penalties which are £10 per day – for up to 90 days. Further penalties are applied when the tax return reaches six and 12 months overdue. Those penalties are the higher of £300 or 5% of the tax outstanding. Each of these penalties are in addition to one another and not in place of.
Late payment of tax
If you cannot pay your tax on time, you will also face late payment interest. If you are aware now that you will not be able to pay your tax on time, it is important to speak to HMRC and you may be able to set up a Time to Pay arrangement with HMRC.
Late payment interest is currently charged at 7.75%, and HMRC may use a determination of tax to issue you with an interest charge. If you pay your tax later than 30 days late additional penalties will apply.
If you would like any advice or assistance in this area, please contact us on 01480 592 002 or use our simple online contact form to arrange a free initial consultation.
Frequently Asked Questions
If you make a mistake on your self-assessment tax return, you should speak to your accountant. You may also want to discuss it with HMRC to determine whether you need to amend your tax return.
If you do need to amend your tax return, and it is within 12 months of the self-assessment deadline you can change your tax return online. If you need to amend a tax return and this deadline has passed you must write to HMRC setting out the changes and implication to your tax liability.
If you miss the deadline for your self-assessment tax return, it's important to speak to your accountant or HMRC as soon as possible. The sooner you rectify the issue and get the tax return filed and tax paid the better.
If you are late, you'll receive an automatic late filing penalty. You'll also be charged interest on late tax payments.
The deadline for completing a self-assessment tax return is 31st January, when completing this online. If you want to submit a paper tax return, the deadline is 31st October.
There are lots of benefits to getting ahead with your tax return, to find out more visit our self-assessment pages.
Last updated 12 Feb 2026 | First published 25 Jan 2022
This article is intended to inform rather than advise and is based on legislation and practice at the time. Taxpayer’s circumstances do vary and if you feel that the information provided is beneficial it is important that you contact us before implementation. If you take, or do not take action as a result of reading this article, before receiving our written endorsement, we will accept no responsibility for any financial loss incurred.
Helen Wood, CA
Helen is a qualified chartered accountant (CA) and joined TaxAssist in 2025 following three years as a freelance content writer for clients in the tax and accounting publishing sector. Prior to this, She spent 17 years at Big Four and Top 10 accountancy firms. Helen writes clear and helpful articles on tax and accounting for businesses and individuals.
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