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HMRC letter codes · Self Assessment (SA)

SA103SSelf-employment pages, short

Last reviewed 14 October 2026 · How Tax Letters checks its facts

In short

GOV.UK says the SA103S is the short version of the self-employment supplementary pages, for people who are self employed, have relatively simple tax affairs and had annual business turnover below the VAT threshold for the tax year.

“If you’re self employed, have relatively simple tax affairs and your annual business turnover was below the VAT threshold for the tax year, use the SA103S short version of the self-employment supplementary pages when filing your SA100 tax return.”

GOV.UK: Self Assessment: self-employment (short) (SA103S) · checked 14 October 2026

Information, not advice: this page reports what HMRC, GOV.UK and the bodies named publish about SA103S. Each fact has its source and the day it was checked beside it.

What it asks

GOV.UK's tax return forms page says you might need to fill in more sections, known as 'supplementary pages', if you are telling HMRC about certain types of income. It lists the SA103S supplementary pages for self-employment, alongside the SA103F supplementary pages.

“You might need to fill in more sections, known as ‘supplementary pages’, if you’re telling HMRC about these types of income: … self-employment - SA103S supplementary pages or SA103F supplementary pages”

GOV.UK: Self Assessment tax return forms · checked 14 October 2026

How to send it or apply

GOV.UK's guidance on completing the tax return, which lists SA103S: Self-employment (short) among its supplementary forms, says you can file your tax return online and do not have to complete it all at once.

“You can file your tax return online … you do not have to complete it all at once … SA103S: Self-employment (short)”

GOV.UK: Complete your Self Assessment tax return for the last tax year · checked 14 October 2026

Free help and HMRC contacts

For Self Assessment queries about returns, payments, replacements or notices, GOV.UK's general enquiries page gives the number 0300 200 3310 and links to information about call charges. The page does not name SA103S.

“Call HMRC if you have a query about: … your Self Assessment returns, payments, replacements or notices … Telephone: 0300 200 3310 … Find out about call charges”

GOV.UK: Self Assessment: general enquiries · checked 14 October 2026

Free help first

These routes are described by GOV.UK, TaxAid and Citizens Advice themselves.

  • HMRC's extra supportHMRC offers extra support if your health condition or personal circumstances make it difficult to contact HMRC, for example a mental health condition, financial hardship or being treated in hospital.
  • Someone to deal with HMRC for youYou can authorise a friend, relative or voluntary organisation to talk to HMRC for you and help you fill in forms.
  • TaxAidTaxAid helps people with tax problems who cannot pay for advice. Tax Help for Older People merged with TaxAid in July 2025.
  • Citizens AdviceCitizens Advice gives confidential advice online, over the phone and in person, for free.