How to file your self-assessment tax return

Blogs 24 Apr 2023

A self-assessment tax return can look daunting but, if you’re prepared and understand exactly what’s asked of you, it’s a lot simpler than it looks.

Business owner doing paperwork with laptop


This article was first published in First Voice. Written by Oumesh Sauba, founder and CEO, MYT Limited.


If you’ve recently become self-employed the first thing on your mind is probably how to file your self-assessment tax return. A self-assessment tax return can look daunting but, if you’re prepared and understand exactly what’s asked of you, it’s a lot simpler than it looks.

Do I need to fill in a self-assessment tax return?

If you are self-employed or freelance and earn more than £1,000 per month you’ll need to file a self-assessment tax return. HMRC will class you as self-employed if you run your own business or are responsible for its success or failure. You might also need to file a self-assessment tax return if you have untaxed income from tips and commission, savings, investments and dividends.

For a more detailed breakdown on who needs to fill in a return you can visit the HMRC website.

How do I register for self-assessment tax?

Once you’ve found out you need to fill in a self-assessment tax return the next step is to register. You’ll need to register with HMRC by the 5 October in your business’s second tax year.

You can register via the government’s self-assessment website. When registering, make sure you have all your freelancing and self-employment details to hand. Once registered, you’ll be given a Unique Taxpayer Reference (UTR). You’ll then need to set up a government gateway account if you don’t have one already and then use the instructions on your UTR to submit your self-assessment form online.

How do I fill in my tax return?

If you’ve never filled in a tax return before it can seem daunting, but the most important tip is to be prepared. For self-employed, you’ll need to submit your income and expenditure details, so you’ll need to make sure you’ve kept any receipts or invoices. You’ll also be able to claim for things like travel expenses, business insurance, marketing and your office, so keeping accurate records and details of these expenditures is vital.

Before you start filling in your tax return make sure you have these items to hand:

  • Your 10-digit Unique Taxpayer Reference
  • Your National Insurance number
  • Details of your untaxed income from the tax year
  • Records of any expenses relating to self-employment
  • Any contributions to charity or pensions that might be eligible for tax relief
  • P60 or other records

Once you have submitted your form, you’ll get a confirmation message and a reference number. HMRC will then take it from there and calculate the tax you owe as well as any National Insurance contributions you’ll need to pay.

What are the deadlines?

It’s important you make all the self-assessment tax deadlines as you may receive a penalty if it’s late through HMRC’s points-based system. 

  • Paper tax returns need to be submitted by midnight 31 October
  • Online tax returns need to be submitted by midnight 31 January
  • Pay the tax you owe by midnight 31 January

How can I simplify the process?

If you’re following the government rules for Making Tax Digital (MTD), you’ll know that by April 2024, income tax filing for self-employed business owners and landlords must be made digitally.

The aim of the government’s MTD initiative is to make it easier for individuals and businesses to submit accurate tax records and keep on top of their finances. To do this, businesses must start using compatible software to manage their tax affairs with HMRC and to submit their tax returns. When searching for compatible software, make sure it allows you to submit returns directly to HMRC without using bridging software.

Getting your tax return in order doesn’t need to be a scary affair. By understanding how to file your return now and after the MTD deadline you’ll be smooth-sailing into the world of self-employment.

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