Your First Self Assessment Tax Return: What to Expect

Aug 4, 2025

Just started working for yourself? Congrats! Whether you’re freelancing full-time, renting out a flat or starting a side hustle, filing your first Self Assessment tax return might feel a little overwhelming.

But good news, tax returns don’t have to be scary at all. It can feel confusing the first time, sure. But once you know what to expect, it’s a lot more doable. And Buzz is here to help every step of the way.

So what even is a Self Assessment?

If you’re self-employed or earning income that isn’t taxed at source (i.e. taken from your paycheck), you need to tell HMRC what you made and what you spent. That’s what Self Assessment is for.

It’s a once-a-year form where you share your income, claim your expenses, and find out what tax you owe.

Who needs to do one?

You probably do if you:

  • Earned more than £1,000 from self-employment
  • Let out a property
  • Took in untaxed income (like dividends or overseas income)
  • Claimed Child Benefit and earn over £50,000
  • Are a director who takes dividends

Not sure? Buzz can help you check.

How to get started

If this is your first time, you’ll need to register with HMRC by 5th October. 

HMRC will then send your UTR (Unique Taxpayer Reference) and a code to activate your online account. But, don’t leave this too late, your UTR comes by post and can take a few weeks. 

What to include in your tax return

You’ll need to have:

  • Your UTR and National Insurance number
  • Details of all income (business, rental, employment, savings, dividends)
  • A record of expenses you want to claim (think: travel, phone, tools, software)
  • Any tax you’ve already paid

Good news! Buzz helps you track this all year so you’re not scrambling to find everything when it comes to Self Assessment time. 

How to file

You can file online with HMRC.

Or, customers on Buzz’s Standard or Premium plan can prepare and file their returns directly using our built-in tools. We’ll guide you through every step of the way, and our team of friendly accountants are on hand if you get stuck. If you need to file for VAT or corporation tax we can help with that too. 

You can file anytime after the end of the tax year (6th April!) Just make sure you get it done by 31st January to avoid a fine.

Buzz makes it simple

We connect to your bank, track your income and expenses, show you what to save, and keep you tax-ready all year.

You might be a Self Assessment beginner, but you’re all pro when it comes to your business. Buzz fills in the gaps with smart tools and expert support to keep you one step ahead. Sign up today to take the guesswork out of tax.

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