If you’re self-employed, a sole trader, or earning income outside PAYE, you’ll need to complete a Self Assessment tax return. Many people search for how to file self assessment tax return because the process feels overwhelming at first. The good news is, once you understand the steps, it becomes much easier to manage. This guide will walk you through your first Self Assessment in plain English.
What is a self assessment tax return?
A Self Assessment tax return is HMRC’s way of collecting Income Tax from people who don’t have it deducted automatically through PAYE. That includes self-employed workers, CIS subcontractors, landlords, and even those with dividends or side hustles. Filing one means telling HMRC about your income and expenses for the tax year, then paying the right amount of tax and National Insurance.
For a more detailed breakdown of who needs to file, check out our Self Assessment tax return guide.
Step 1: Register with HMRC
Before you can file, you need to register with HMRC for Self Assessment. Once registered, you’ll get a Unique Taxpayer Reference (UTR) number. This can take a couple of weeks to arrive, so don’t leave it until the last minute.
Step 2: Gather your records
HMRC expects accurate figures. Collect your invoices, receipts, bank statements, P60s (if you had PAYE work), and any CIS deduction statements if you’re a subcontractor. Keeping things organised makes the actual filing process much smoother.
Step 3: Fill in your return
You can file online through HMRC’s website or use an accountant. The online system guides you through sections, but you’ll need to know which apply to you – self-employment pages, property income, capital gains, and so on.
If this is your first self assessment guide, remember:
- Enter your income in the right sections.
- Claim allowable expenses (tools, travel, office costs, etc.).
- Double-check figures before you submit.
Step 4: Submit and pay
The tax year runs from 6 April to 5 April, with online filing deadlines on 31 January. That’s also when any tax due must be paid. HMRC may also ask for “payments on account” towards next year’s bill.
If you’re late, expect penalties – so it’s worth filing early to avoid stress.
Extra tips for first-timers
Many first-timers worry about missing expenses. The truth is, HMRC allows a wide range of deductions, from mileage to protective clothing. Our Self Assessment FAQs explain common claims in detail.
Another thing to note is Making Tax Digital (MTD). From April 2026, self-employed workers earning over £50,000 will need to keep digital records and send updates every quarter. This is being phased in, so it’s worth preparing now.
Filing yourself vs using Tax2u
Here’s a quick look at the difference between doing your return alone and letting Tax2u handle it for you:
| Filing Yourself | Filing with Tax2u | |
|---|---|---|
| Time Spent | Several hours (gathering, calculating, checking) | 15 minutes to upload your records |
| Risk of Errors | High if you’re new to Self Assessment | Low – checked by tax experts |
| Claiming Expenses | Easy to miss claims and allowances | We identify all allowable expenses |
| HMRC Penalties | Risk if you file late or incorrectly | We keep you on track and compliant |
| Peace of Mind | Stressful if it’s your first time | Done for you with expert support |
Don’t struggle through it alone
Filing your self employed tax return UK step by step doesn’t need to be stressful. At Tax2u, we’ve helped thousands of first-time filers get it right and often save money by claiming expenses they didn’t realise they could.
Get started with your Self Assessment today and let us take the hassle out of the process.