Why Self-Assessment Deadlines Matter
If you’re self-employed, a landlord, or receive untaxed income, filing a self-assessment tax return is essential. Missing a deadline could lead to automatic fines, even if you don’t owe tax. Knowing the key dates and requirements helps you avoid stress and unnecessary penalties.
Who Needs to Complete a Self-Assessment?
- You may need to file a self-assessment tax return if you:
- Are self-employed
- Earn more than £1,000 from a side income
- Receive rental income
- Have dividends or capital gains
- Are a partner in a business
- Have income from abroad
If unsure, you can check HMRC’s guidance here
Key HMRC Deadlines
31 October (Paper Returns)
If you’re filing a paper return, it must reach HMRC by 31 October following the end of the tax year.
31 January (Online Returns & Payment Due)
The most common method is online. You must:
- File your return by midnight on 31 January
- Pay any tax you owe by this date too
5 October (New Registrations)
If you’ve never filed a tax return before, you must register for self-assessment by 5 October following the tax year in which you earned income.
31 July (Second Payment on Account)
If you make payments on account, your second instalment is due by 31 July each year.
Late Filing Penalties
- 1 day late: £100 automatic fine
- Up to 3 months late: £10 per day (up to 90 days)
- 6 months late: Additional £300 or 5% of the tax due (whichever is higher)
- 12 months late: Further £300 or up to 100% of the tax due in serious cases
Late Payment Penalties
- 30 days late: 5% of tax unpaid
- 6 months late: Additional 5%
- 12 months late: Additional 5%
Interest also accrues daily on any unpaid amounts.
How to Avoid Penalties
- Mark key dates in your calendar
- Keep accurate records throughout the year
- File and pay early to avoid the rush
- Use cloud accounting software to stay organised
- Work with an accountant to ensure accuracy
Need Extra Time?
In rare cases, you may be able to appeal a penalty if you have a ‘reasonable excuse’ (e.g. illness, bereavement, software failure). More details are available here
Why Work with A Wigglesworth & Company?
Filing your tax return can be time-consuming and stressful, especially if you’re juggling other business demands. Based in Doncaster and trusted by clients across the UK and overseas, A Wigglesworth & Company offers tailored self-assessment support to ensure your returns are accurate, compliant, and submitted on time.
Get Help with Your Self-Assessment Today
Whether you’re filing for the first time or need help managing multiple income streams, we’re here to help. Contact us now and let A Wigglesworth & Company take care of your self-assessment with confidence.