The SA103 Form is a supplementary page you may need to use if you submit a paper version of the Self Assessment tax return and need to report any self-employment income to HMRC.

You only need to fill in an SA103 Form if you make money from self-employment and submit your Self Assessment tax return using a paper form. If you run a limited company then you’ll report the company’s income and expenses using a Company Tax Return. You don’t need to complete a separate SA103 postal form if you submit your Self Assessment online.

There are two different versions of the form, so you’ll need to use the right one based on your turnover for the year:

• SA103F if your annual turnover was more than the VAT registration threshold for the tax year, or if you’ve changed your accounting date
• SA203S if your annual turnover was below the VAT registration threshold in that tax year and your tax is fairly straightforward

If you have more than one business, then you’ll need to fill in a separate form for each one. HMRC provide more detailed guidance on completing the form on their website, but it’s normally a case of providing the details about any income the business received, as well as your allowable expenses.

Including your expenses means that you can claim tax relief against the money that your business spends, helping to reduce the tax bill that you need to pay.

It can be a bit confusing, but you don’t need to include the details of income you receive as a company director on your SA103 Form. This is because it’s classed as a type of employment or ‘office’. If you need to tell HMRC about this type of income, you should also complete an SA102 Form.

The SA103 Form is available to download from the HMRC website, along with the main SA100 tax return form. Once you’ve entered all of the information, post your return to the address shown on the form.

The deadline for submitting a paper return is a bit earlier than if you submit online, so make sure your forms reach HMRC before 31st October!

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