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May 1 2024

What is an SA103 form?

If you are someone that needs to pay their own income tax due to being self-employed, you need to be aware of the SA103 form. These supplementary tax forms contain details about the work you complete as part of your self employment. As someone who works for themselves, it can be difficult to find the time to plan. In this article, we explain the main points that you need to know about SA103 forms, such as what needs to be included in them and when they need to be sent.


What is the SA103 form for?

A SA103 form is designed to be submitted alongside the SA100 Tax Return form, also known as a Self Assessment tax return. You will only be required to fill out this form if you are classed as self employed. Confusingly, this doesn’t include those using a limited company to do business. Instead, SA103 forms are required to be filled out by freelancers and sole traders.

The SA103 form contains a number of sections each with boxes that must be filled out. The information includes details about the business, its income, expenses, capital allowances, taxable profit and loss, and liabilities. As someone who’s self employed, submitting this form is important as it can help reduce your tax bill by allowing you to claim relief against the money you’ve spent for business purposes.


Which version of the SA103 form should I use?

Generally, if your annual turnover was less than the VAT registration threshold for the tax year, you will need to submit the SA103S (short) form. If your turnover exceeds the threshold, or your accounting period has changed, you should complete the SA103F (full) form. The turnover threshold for VAT registration is £85,000 at the time of writing. There are a range of additional conditions which, if met, also mean that you should use the SA103F form. This applies if:

  • You’ve changed your accounting basis, leading to adjustment income.
  • You’re currently claiming Overlap relief.
  • You were within the Managing Serious Defaulters (MSD) programme during the business year.
  • Your income for your basis period is over £1000 and your taxable self-employed period is different to your accounting period.
  • You are required to adjust any profits to Class 4 National Insurance Contributions.

While most self-employed workers will use the short form, this will always depend on the individual’s situation. It’s simply not worth the risk of submitting supplementary tax forms that are incorrect or filled out incorrectly. If you’re unsure, or you want to save yourself time and energy, seek help from a chartered accountant.

When to submit the SA103 form

You can submit the SA103 online or in a paper version, although we recommend doing it online. It’s more straightforward and it gives you another 3 months to do it from the start of the business year (October 31st compared to January 1st).


Looking for sole trader accountants?

At Jan McDermott Chartered Accountants, we provide services for a range of businesses as well as sole traders. This includes limited companies, start-ups, and more. Our team of chartered accountants in the Wirral are experienced in supporting those in Birkenhead and the Liverpool region. We have the knowledge to draw up tax returns and associated documentation correctly, when it needs to be submitted throughout the year. Whether it’s your first year being self employed, or you’re a seasoned sole trader, don’t hesitate to contact Jan McDermott Chartered Accountants if you have any questions.