Do I need to register for Self Assessment
Not everyone who earns money outside employment needs to register for Self Assessment. Here's a plain-English guide to who needs to register, when, and how.
7/1/20262 min read
Do I need to register for Self Assessment?
Self Assessment is HMRC's system for collecting tax from people whose income isn't fully taxed through PAYE. If you're self-employed as a sole trader, you'll almost certainly need to register - but there are a few situations where you might not.
The main trigger: the £1,000 trading allowance
If your gross self-employment income in a tax year is more than £1,000, you need to register for Self Assessment and file a tax return. This is the trading allowance threshold - the £1,000 figure applies to your total income before any expenses, not your profit.
So if you earn £1,100 from freelance work, even if your expenses are £400 and your profit is only £700, you've crossed the threshold and need to register.
If your income is £1,000 or less, you don't need to register - though there are some reasons you might choose to anyway (see below). We cover the trading allowance in more detail in our separate post:
If your income is £1,000 or less, you don't need to register - though there are some reasons you might choose to anyway (see below). We cover the trading allowance in more detail in our upcoming post on What is the trading allowance?
Other reasons you might need to register
Self Assessment isn't just for sole traders. You may also need to register if:
• You're a company director
• Your total income (from all sources) is over £100,000
• You have untaxed income above £2,500 - for example from property rental or investments
• You need to claim certain tax reliefs, such as higher-rate pension tax relief
• HMRC has sent you a notice to file a return
When to register
The deadline to register is 5 October following the end of the tax year in which you started trading. So if you started self-employment during the 2025/26 tax year (which runs from 6 April 2025 to 5 April 2026), you need to register by 5 October 2026.
Don't leave it until you're ready to file your return - the registration itself takes time. Once registered, HMRC sends your Unique Taxpayer Reference (UTR) by post, which can take up to 21 days.
How to register
You register online through HMRC's Government Gateway. If you don't already have a Government Gateway account, you'll create one as part of the process. You'll need your National Insurance number and some basic personal details.
Once you've registered, HMRC will confirm and send your UTR by post. Keep it safe - you'll need it every year.
We cover the full registration process in more detail in our post on
We cover the full registration process in more detail in our post on setting up as a sole trader.
Reasons to register even if you're under the threshold
There are a couple of situations where it might be worth registering even if your income is under £1,000:
• To pay voluntary Class 2 National Insurance contributions - this protects your State Pension entitlement and eligibility for certain benefits.
• To claim a trading loss - if your business made a loss in its first year, registering lets you carry that loss forward to offset against future profits.
What if you don't register when you should?
If you miss the 5 October registration deadline, register as soon as you realise - late registration is better than not registering at all. HMRC may charge a penalty for late registration depending on how much tax was owed and how late you were, but they take a more lenient approach if you come forward voluntarily rather than waiting to be found.
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