10 frequently asked questions about Self Assessment – answered by HMRC

Freelance

Whether you’re a new business owner, have invested in a rental property, started a side hustle or sold assets between 6 April 2024 and 5 April 2025 chances are you’ll have to pay tax on your earnings and that means Self Assessment.

Last year more than 4.2 million Self Assessment tax returns were filed by women so it’s worth outlining what Self Assessment means for them. 

The 31 January 2026 deadline for filing your Self Assessment and paying the tax you owe is fast approaching, so Jashoda Pindoria from HM Revenue and Customs (HMRC) helps explain what Self Assessment is and what you may need to do by answering 10 of the most frequently asked questions.

1) What is Self Assessment?

Self Assessment is how the self-employed and sole traders pay tax on their income. People are usually taxed automatically through their pay from their employer, but if you’re self-employed as a contractor or freelancer or if you haven’t been automatically taxed, for instance you rent out a property, you may need to declare your income by completing a tax return and then pay any tax owed. The current Self Assessment reporting period is for 6 April 2024 to 5 April 2025.

2) I think I might need to do a tax return this year. How do I check?

If you’re new to Self Assessment and not sure where to start, you can use the ‘check if you need to send a tax return’ tool on GOV.UK. You simply answer a few straightforward questions and the tool helps you decide if you need to complete a tax return.

3) How do I get started?

If you are new to Self Assessment for the 2024 to 2025 tax year,  you’ll first need to register for Self Assessment. You can watch our helpful YouTube videos which take you through the online registration process every step of the way.

Once you have registered, HMRC will send you your Unique Taxpayer Reference (UTR) – a 10 digit reference number that is used to identify your Self Assessment tax record. Your UTR is also stored in the HMRC app or your online account. 

You can complete your tax return online via GOV.UK. When you’re ready to start your tax return you’ll need your UTR and National Insurance number, as well as details of your income, earnings, savings interest and other financial records.

4) It seems daunting to me, where can I go for help?

HMRC wants to help you get your tax right so there’s a lot of helpful guidance on GOV.UK to advise you how to complete your tax return including:  

• a wide range of ‘how to’ and ‘explainer’ videos as well as live webinars that you can join where you can ask questions, or if you cannot attend, you can watch them on demand
• tools that includes HMRC’s digital assistant, self-employed tax calculators and the HMRC app.

There’s also specific guidance for the various reasons you could be completing a tax return, for example if you’re filling out a Self Assessment because of your side-hustle earnings and regularly sell goods or provide services through an online marketplace, then have a look at HMRC’s information sheet on selling online and paying taxes. 

5) When is the deadline?

The deadline for submitting your Self Assessment return online and paying your tax for the 2024 to 2025 tax year is 31 January 2026. If you miss the deadline, you could incur penalties. 

If you have paid too much tax, we’ll let you know and repay you once we’ve processed your Self Assessment return. You can also check if you’re due a refund in the HMRC app once you’ve filed your return. 

6) What information do you need to include on your return?

You’ll need to include all your taxable income on your tax return so you can pay any tax owed. So that’s any income you have already paid tax on (for example, if you’re employed and paid Income Tax and National Insurance through PAYE) as well as any expenses so we can accurately calculate if any tax is due.

You’ll also need to include information on any contributions you’ve made to charity or pensions that may be eligible for tax relief.

Make sure you keep records such as bank statements, invoices, contracts and receipts for your income and outgoings.

7) Can I ask someone else to fill my Self Assessment in for me?

Yes, you can authorise an agent to manage your tax affairs (such as an accountant or tax adviser) or ask a friend or relative or give someone power of attorney to act on your behalf. More information on this can be found here Appoint someone to deal with HMRC on your behalf. But it’s worth remembering it remains your responsibility to ensure the return is accurate and submitted on time.

Please do not share your HMRC login details with anyone, including your tax agent.

8) How do I pay?

The deadline to pay any Self Assessment tax owed is 31 January 2026 and the quickest and easiest way to pay is through the HMRC app.

If you think you may struggle to pay your tax bill, please get in touch with us to let us know. There are a range of payment options, that could be available to you including a Budget Payment Plan where any payments you make will be used to pay your next tax bill.

You may be able to set up a payment plan yourself. The plan, known as a ‘Time to Pay’, means eligible customers can arrange to pay their tax bill in regular instalments over an agreed period. 

9) Will I need to do Self Assessment next year?

If you continue to meet the Self Assessment criteria in the ‘check if you need to send a tax return’ tool on GOV.UK you need to continue to file a Self Assessment tax return. 

If your circumstances change and you no longer believe you need to complete a tax return, then you must tell HMRC as soon as the change happens. You can find out how to stop your Self Assessment through our online videos. 

Don’t ignore an HMRC letter remining you to complete a tax return, even if you think you haven’t got anything to pay. Get in touch with us if you don’t think you should complete one as you could receive a penalty if we’re expecting a return and don’t receive one.  

10) I’m self-employed and do Self Assessment, so is there anything else I need to do?

You need to make sure you are registered with HMRC as self-employed. This applies to those who have been working for themselves for a while and people who are newly self-employed. You can find out more information about registering as a sole trader and setting up a business partnership on GOV.UK.