If you earn money from being self-employed then you might need to submit a Self Assessment tax return to tell HMRC about your income. In this article we explain how Self Assessment works if you’re self-employed, and what information you might need to include.
Do I need to complete a Self Assessment if I’m self-employed?
If you’re self-employed, for instance because you’re a sole trader or you freelance, you’ll normally need to register for Self Assessment and submit a tax return if your self-employed or property income is more than the £1,000 trading allowance in a tax year (which runs 6th April – 5th April).
Key point to remember
Once you register, you must continue to submit a Self Assessment tax return every year unless you tell HMRC you no longer need to (and they confirm this is the case).
So if you register for Self Assessment one year, but then earn less than the £1,000 trading allowance the following year (or even if you make a loss), you still need to send a return.
Failure to submit a tax return when HMRC are expecting one usually results in a penalty!
What about if I start using Making Tax Digital?
Some self-employed people need to use Making Tax Digital for Income Tax depending on how much they earned in the tax year. If this applies to you it means you can send quarterly updates about your self-employed income and expenses throughout the year, followed by a complete return for the year once it ends – and this replaces the Self Assessment tax return.
The ins and outs of it are a bit more detailed, so we have a separate article which goes over how to work out whether you need to use Self Assessment or Making Tax Digital for Income Tax instead.
Do I still need Self Assessment if I work for an employer at the same time?
You’ll still need to register for Self Assessment if your self-employed income is more than £1,000, even if you work for an employer as well as being self-employed (for example, because you have a side hustle you work on in your spare time).
This is because your employer will only report on earnings relating to your employment with them, so it’s up to you to tell HMRC about any income you get from working for yourself. If you ask an accountant to submit your return for you, make sure you tell them about any employments and other income as well as your self-employed activity!
How does Self Assessment work for self-employed people?
People who work as an employee usually have their tax and National Insurance contributions taken care of by their employer. If you also earn money from self-employment, then it’s up to you to report your income and pay the right amount of tax and NI (although the NI you pay as a self-employed person is different to NI you pay through an employer).
What sort of income do sole traders need to report?
Your Self Assessment tax return must show the details of all the income you receive during the tax year, including anything you earn from an employer. It doesn’t mean you’ll need to pay tax on that money again!
HMRC use this information to work out your total earnings for the year so they can calculate what rate of tax you should pay on your self-employed income. Declaring all your income for the year helps HMRC understand:
- What you earned
- How you earned it
- What tax relief you might be entitled to (for instance, by claiming allowable expenses)
- Any tax you’ve paid already, so you don’t end up paying it twice on the same money
Our free calculator will help you estimate your self-employed tax bill.
When should I sign up as self-employed?
The deadline for registering as a self-employed sole trader is 5th October following the end of the tax year in which you started trading.
For example
If you start your business in November 2025:- Your first tax year is 2025/26
- Your second tax year runs 2026/27
How do I register?
Registering for Self Assessment doesn’t happen automatically, but you can sign-up online. If you have any issues, HMRC have a Self Assessment Helpline available on 0845 900 0444, and you can also contact contact them if you have issues signing in to your Self Assessment account in the future.
When should I submit my self-employed tax return?
The deadline for submitting your Self Assessment tax return depends on how you plan to submit. If you’re our client, you can see upcoming deadlines and what to do next in Client Hub.
| Action | What you need to do | Deadline |
| Register for Self Assessment | If you need to send a tax return for 2025/26 but didn't need to for the previous year, you should register for Self Assessment by this date. | 5th October 2026 |
| Submit a paper tax return | The deadline for submitting your Self Assessment tax return if you use a paper form. | Midnight, 31st October 2026 |
| Submit a tax return if you want to pay your bill through PAYE | Request that HMRC collect any tax you owe through your tax code. | Midnight, 30th December 2026 |
| Submit a tax return online | This is the deadline for submitting your tax return if you submit online. | Midnight, 31st January 2027 |
| Pay your Self Assessment tax bill | You should pay your tax bill in full by this date in order to avoid penalties. | Midnight, 31st January 2027 |
You don’t have to wait until the deadline to submit your tax return, and can file it as soon as the tax year is over. This gives you much more time to get it right, and more time to pay your tax bill!
Learn more about our online accounting services for businesses. Call 020 3355 4047 to chat to the team, and get an instant online quote.
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