5 things to know about your self assessment tax return

14 January, 2025 · 10 min read

Updated: 14 February, 2025

Author

Team ANNA

Zoooooom. What’s that sound? It’s the self assessment online deadline whizzing towards us. That’s right, if you’re self-employed you’ve got until 31 January 2025 to file your self assessment online tax return for the tax year April 2023 to 2024. So we’ve put together a little list of 5 things you need to know.

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1 Find out if you need to do one

Most UK taxpayers don’t need to file a self assessment tax return because they are employees that are paid PAYE (where the tax and National Insurance is deducted at source before it reaches their bank account). However, if you’re self-employed, a self assessment tax return may be on your horizon. So, who needs to do one?

You’ll need to file a self assessment tax return if during the last tax year:

you were self-employed as a ‘sole trader’ and earned more than £1,000 (before taking off anything you can claim for expenses)
you were a partner in a business partnership
you had a total taxable income of more than £150,000
you had to pay Capital Gains Tax when you sold or ‘disposed of’ something that increased in value

There may be other circumstances where you need to file a self assessment tax return, for example if you made money by renting out a property.

2 Don’t delay

Don’t panic - you’ve still got a couple of weeks before you need to file your self assessment tax return, so get started now rather than sticking your head in the sand and hoping for the best. If you do file late, you’ll almost certainly be hit with a £100 penalty, so it’s worth getting on with it.

3 Have your information at hand

To properly complete your self assessment tax return, you’ll need these essentials

Your Unique Taxpayer Reference (UTR) and National Insurance number. Your UTR is found on any correspondence received from HMRC in relation to your self-assessment – including on the tax return reminders that HMRC sends every year.
Records of income (e.g., invoices, P60s, bank statements).
Details of expenses you plan to claim (things like office supplies or travel costs).
Information about other sources of income (e.g., savings, investments).

If you have all those, you should have all the info you need to complete your self assessment.

4 If you work from home, don’t forget to claim

Many of us now work from home, at least some of the time. And that means that you can claim some expenses on your tax return.

You can either claim a simplified flat rate, which works out as £26 a month, or you can make a more detailed claim.

If you want to calculate actual costs, you can claim a portion of your household bills based on how much of your home is used for work. For example:

Utilities: Gas, electricity, water bills.
Internet and phone bills: Work-related usage only.
Council Tax: A proportional amount based on work use.

For instance, if you use one room in a five-room house exclusively for work 40% of the time, you can claim 8% of these costs (1/5 × 40%). Don’t forget to keep detailed records of calculations!

Handily, ANNA has its own Working From Home calculator you can use.

5 Keep records!

Whatever expenses you’re claiming, it’s really important to keep records, as HMRC may need them. If you buy something, take a photo of the receipt. Happily, with ANNA you can snap pics of your receipts and they’ll automatically be scanned, read, categorised and stored. So no more keeping receipts in a shoebox!

Do you operate as a Limited Company?

Also, remember that if you’re the director of a Limited Company and you’re paying yourself a dividend, you’ll almost certainly have to fill in a self assessment tax return. Want to know the best way to pay yourself as a director? Check out our Income Tax and Salary calculator here.