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The SA103 is a form that can be submitted alongside an SA100 if the individual earns income from self-employment. There are two different versions of the form.

More detail:

The SA103 is a one of the main tax forms used in the United Kingdom for Self Assessment. It is a supplementary form you submit alongside the main tax return used by individuals that declare income from Self-employment.

There are two versions of the SA103:

  • The SA103S (S for Short) is used if income from Self-employment was less than £85,000
  • The SA103F (F for Full) is applicable if income from Self-employment was £85,000 or more.

It is a paper form and must be submitted alongside an SA100 by 31st October following the end of the tax year that the form relates to.

If an individuals submits a Self Assessment online, an SA103 is not required as the online form will include the ability to file the information there.

An example page of the SA103F from 2022/23 is shown below:

A photo of page 3 of a blank SA103F form from 2022/23

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