Do I need to file a Self Assessment tax return?

If you’ve earned money that hasn’t already been fully taxed, you may need to complete a Self Assessment tax return. For some people it’s obvious. For others, a side hustle, rental income or a few different income streams can make things feel a bit foggy.

Who usually needs to look at Self Assessment?

You’ll commonly need to check your position if you were:

• self-employed as a sole trader and earned more than £1,000 before expenses
• a partner in a business partnership
• receiving untaxed income, such as money from property, tips or commission, savings interest, dividends or foreign income
• in a situation where Capital Gains Tax is due
• liable for the High Income Child Benefit Charge and it is not being collected through PAYE
• asked by HMRC to send a tax return.

And yes — you can still need Self Assessment even if you already have a normal PAYE job.

The important dates for 2025/26

Our little bit of advice? Don’t leave it until a rainy Manchester night on 30 January with six coffees and a bag of receipts. 😅 Getting organised earlier is much kinder to future you.

What should I keep?

Good records make everything easier. Depending on your circumstances, keep things like invoices, receipts, income records, business expenses, bank statements, property income and costs, dividend information and anything else relating to money you’ve earned.

You do not need everything beautifully organised before speaking to an accountant. We’ve seen plenty of receipt piles over the years!

Can I do my own tax return?

Absolutely. Plenty of people file their own Self Assessment return. An accountant can be useful if you’re unsure what needs declaring, what expenses may be relevant, your circumstances have become more complicated, or you simply don’t fancy spending your evening trying to make sense of forms.

What if I’m late?

HMRC can charge penalties for late filing and interest or penalties for late payment. If you think you’ve missed something, the best thing is usually to start sorting it rather than putting the letter back in the drawer.

Quick questions

A few common ones.

I’m employed — can I still need Self Assessment?

Yes. You may still need a return if you have additional untaxed income or another reason that requires you to report to HMRC.

My side hustle made less than £1,000. Do I need one?

HMRC’s main Self Assessment requirement for a sole trader applies where gross trading income is more than £1,000 before expenses. Your wider circumstances can still matter, so check if you’re unsure.

When is the online deadline?

For the 2025/26 tax year, the standard online filing deadline is 11:59pm on 31 January 2027.

Can an accountant submit it for me?

Yes. You can authorise an accountant or tax adviser to help prepare and submit your return.