Confused about Self Assessment? ETAXPOL breaks down exactly what sole traders in the UK need to do, when to do it, and how to avoid common (and costly) mistakes.
If you’re self-employed in the UK, Self Assessment is one of those things you simply can’t ignore. Yet every year, thousands of sole traders either miss the deadline, underpay, or overpay — all because no one sat them down and explained it clearly.
That’s what we’re here for.
What is Self Assessment, and who needs to file?
Self Assessment is HMRC’s system for collecting Income Tax from people whose tax isn’t automatically deducted through PAYE. If you’re self-employed — whether you’re a builder, cleaner, IT consultant, food trader, or anything in between — you almost certainly need to complete a Self Assessment tax return each year.
You also need to file if you earned more than £1,000 from self-employment, even if it’s a side income alongside a regular job.
Key dates to keep in your diary
The UK tax year runs from 6 April to 5 April the following year. Here are the deadlines you need to know:
- 31 October — paper tax return deadline
- 31 January — online tax return deadline (and payment of any tax owed)
- 31 July — second payment on account (if applicable)
Miss the 31 January deadline and HMRC will issue an automatic £100 fine — even if you owe no tax at all. The penalties increase the longer it goes unfiled, so getting organised early really does pay off.
What can you claim as a sole trader?
One of the biggest advantages of being self-employed is that you can deduct allowable business expenses from your income before calculating tax. This includes things like:
- Travel and mileage used for work
- Tools, equipment, and materials
- A portion of your home utility bills if you work from home
- Phone and internet costs (business use portion)
- Accountancy fees
Many sole traders leave money on the table simply because they don’t know what they’re entitled to claim. A good accountant will make sure that doesn’t happen to you.
A word on Payments on Account
If your Self Assessment tax bill is over £1,000, HMRC asks you to make advance payments towards next year’s tax — called Payments on Account. These are due in January and July. It catches many first-time filers off guard, so it’s worth understanding this early.
The peace of mind that comes with having support
We know that for many of our clients — especially those who moved to the UK from Poland — navigating a foreign tax system in a second language can feel overwhelming. That’s exactly why ETAXPOL exists.
Our Polish-speaking team handles Self Assessment for sole traders across the UK every single year. We make sure your return is accurate, submitted on time, and that you’re not paying a penny more tax than you should.
If you’d like a friendly conversation about your situation — no jargon, no pressure — get in touch. We’re here to help.