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How to fill in SA103S — the self-employment (short) pages of a Self Assessment return

Form SA103S is the short self-employment supplement to HMRC's Self Assessment tax return (SA100) — two pages covering turnover, expenses, capital allowances and net profit or loss, for a sole trader whose business turnover was under £90,000.

For a personal representative, it reports the deceased's self-employment income and expenses from 6 April of that tax year up to the date they died (or the date trading actually stopped, if earlier) — never the post-death administration period, which is reported separately, not on SA103S.

This walkthrough covers the business-details boxes and where the cessation date goes, turnover and the trading income allowance, the expense boxes and the box 20 shortcut, capital allowances, and the Class 2 National Insurance box that's easy to miss on a low, part-year final return.

✓ Official source checked 23 August 2026 · GOV.UK last revised this form 6 April 2026SA103S on GOV.UK
Free
United KingdomInformational, not legal or financial adviceOfficial source: GOV.UK
Official form · always current

This is the same official SA103S file HM Revenue & Customs publishes on GOV.UK — the link below fetches the current version live from GOV.UK the moment you click it, so it can never go out of date.

Current version: December 2025 · confirmed on GOV.UK 23 August 2026

This walkthrough takes SA103S field by field, for the version a personal representative fills in on a deceased sole trader's behalf. Box 6Q/6 — the date trading actually stopped — carries the date of death, not the tax year end, and claiming the £1,000 trading income allowance rules out every expense and capital allowance box on the rest of the form.

The thing most people get wrong
For a deceased sole trader's final return, box 6Q/6 — did the business cease before 6 April 2026, and if so when — has to carry the true final trading date. That's normally the date of death, not the tax year end and not left blank; getting it wrong distorts the accounting-period box (7) and can misstate the final year's taxable profit, which then feeds into both the deceased's Income Tax bill and the estate's own figures.

Separately, the £1,000 trading income allowance in box 10.1 is mutually exclusive with claiming ANY of the itemised expenses (boxes 11–20) or capital allowances (boxes 23–25.2) — claiming both is a common error, and the allowance cannot be used to create or increase a loss.
The form, in summary
Valoren
SA103S2 pages44 fields guided
With Valoren20 minutes
Without Valoren1–2 hours
pulling every business income and expense figure up to the date of death from bank and business records
Deadline
31 Oct / 31 Jansame SA100 dates —
no separate one
Who Files
Executoror administrator, for
the deceased's final page
£
Fee
Freeattaches to
SA100, no fee
Filed with HMRC
Draws from your Estate File
the records this form is built from
PersonalFinancial Accounts·Digital Access Map·Asset Inventory·Income & Outgoings·Civil Dossier·Policy Index·Legal Instruments·Medical Abstract·Property Folio·Succession Plan·Digital Legacy Registry·Business Interests & Directorships·Funeral & Committal Wishes·Dependent Care & Handoff·Personal Record·RegistryMaster Registry·Renewal Register·People, Authority & Contacts·Designated Places·Kinship & Succession Map·SecureAccess Controls·Recovery Routes·Custody & Contingency·EventsDeath & Estate Activation·Incapacity & Medical Proxy·Absence & Continuity Cover·Access Loss & Identity Recovery·Legal Dispute & Evidence Protocol·Theft & Asset Compromise·Property Damage & Incident Response·Relocation & Address Update Protocol·Separation & Custody Documentation·Business Interruption & Continuity·PersonalFinancial Accounts·Digital Access Map·Asset Inventory·Income & Outgoings·Civil Dossier·Policy Index·Legal Instruments·Medical Abstract·Property Folio·Succession Plan·Digital Legacy Registry·Business Interests & Directorships·Funeral & Committal Wishes·Dependent Care & Handoff·Personal Record·RegistryMaster Registry·Renewal Register·People, Authority & Contacts·Designated Places·Kinship & Succession Map·SecureAccess Controls·Recovery Routes·Custody & Contingency·EventsDeath & Estate Activation·Incapacity & Medical Proxy·Absence & Continuity Cover·Access Loss & Identity Recovery·Legal Dispute & Evidence Protocol·Theft & Asset Compromise·Property Damage & Incident Response·Relocation & Address Update Protocol·Separation & Custody Documentation·Business Interruption & Continuity·
Legal basisStatute

SA103S doesn't create its own filing duty — like SA102, it's a supplementary page attached to SA100, and the underlying obligation sits in sections 7 and 8 of the Taxes Management Act 1970, which only bite once HMRC has issued (or should have issued) a notice to file.

What SA103S reports — trading income, expenses and capital allowances — is charged and computed under the Income Tax (Trading and Other Income) Act 2005 and the Capital Allowances Act 2001. Neither has been checked section-by-section against legislation.gov.uk in this build; treat them as the standard framework rather than a pinned citation.

SA103S is the SHORT self-employment page — it only applies where turnover was under £90,000, the accounting period runs to the standard 31 March–5 April window (or the date trading stopped, if earlier), and none of a handful of complications apply (a change of accounting basis, or membership of HMRC's Managing Serious Defaulters programme). Anyone outside those limits uses the longer SA103F instead.

Section by section

The form, section by section.

Before you start, you’ll need:
  • Who Files — In Valoren's context, this is the personal representative — executor or administrator — completing the final Self Assessment return of someone who was a self-employed sole trader, with turnover under £90,000 and simple affairs, at or before death. The PR fills in SA103S as part of the deceased's SA100 for the tax year death occurred in, covering income and expenses up to the date of death (or the date trading actually stopped, if earlier), and marks box 6Q/6 to show the business ceased. It does NOT cover the estate's own income during the administration period that follows — that's reported separately, not on SA103S — so don't let a personal representative assume this form covers anything after the date of death.
  • 2 pages · 44 fields guided
  • Draws from your Estate File — Financial Accounts
Section 1

Before you start — is SA103S the right form

SA103S is the short version of the self-employment pages. Confirm it actually fits before working through the boxes.

When SA103S applies

Turnover under £90,000 for the period, an accounting period running to the standard 31 March–5 April window (or the date trading stopped, if earlier), no change of accounting basis creating 'adjustment income', and no membership of HMRC's Managing Serious Defaulters programme.

Miss any one of those and the longer SA103F is the correct form instead.

What it covers for a personal representative

The deceased's self-employment income and expenses from 6 April of that tax year up to the date they died, or the date trading actually stopped if that came first — filed as part of the deceased's own final SA100, not as a return for the estate.

What it does NOT cover

Income the estate itself earns during the administration period that follows death — rent, interest, dividends collected after the date of death — is reported separately, not on SA103S. Don't let a personal representative assume this form covers anything after the date of death.

SA103S is the short version of the self-employment pages. Confirm it actually fits before working through the boxes.

HM Revenue & Customs (HMRC) · SA103S
Section 2

Business details — boxes 1–8, and marking cessation on death

Page SES 1 opens with the details that set the shape of everything below it — description, dates, and the accounting method. Box 6 is the one that matters most for a death.

Boxes 1–2 — description and postcode

Box 1 is a free-text description of the business. Box 2 is the postcode of the business address — foster or shared lives carers write 'Qualifying carer' in box 1 instead, and are pointed to a separate HMRC helpsheet; Rent-a-Room scheme claimants write 'Rent-a-Room' and follow a different box path.

Box 3 and 4 — changes and carers

Box 3 is ticked if the business name, description, address or postcode changed in the last 12 months, with details given in the SA100's 'Any other information' box. Box 4 is ticked if the deceased was a foster carer or shared lives carer.

Box 5Q and 5 — if the business started this year

Box 5Q asks whether the business started after 5 April 2025; if yes, box 5 asks for the exact start date.

Box 6Q and 6 — the cessation date, the one that matters for a death

Box 6Q asks whether the business ceased before 6 April 2026; if yes, box 6 asks for the final date of trading. For a deceased sole trader's final return, this is normally the date of death — using the tax year end, or leaving it blank, misstates when the business actually stopped.

Box 7 — the accounting date

The date books and accounts are made up to. It must fall between 31 March and 5 April 2026, or match the final trading date from box 6 — an accounting date outside that window is one of the signs SA103F is needed instead of SA103S.

Box 8 — accounting method

Ticked if using traditional accruals accounting rather than the cash basis.

Page SES 1 opens with the details that set the shape of everything below it — description, dates, and the accounting method. Box 6 is the one that matters most for a death.

HM Revenue & Customs (HMRC) · SA103S
Section 3

Business income — boxes 9–10.1, and the trading income allowance

Only available where turnover was under £90,000, which is the condition for using SA103S at all.

Box 9 — turnover

Takings, fees, sales and money earned by the business, up to the date trading stopped.

Box 10 — any other business income

Business income not already included in the box 9 turnover figure.

Box 10.1 — the £1,000 trading income allowance

An alternative to claiming expenses: up to £1,000 can be deducted instead of itemising costs. Using it means boxes 11–20 and 23–25.2 are all left blank — it cannot be combined with expenses or capital allowances, cannot create or increase a loss, and cannot be claimed at all where the income comes from a connected party.

Only available where turnover was under £90,000, which is the condition for using SA103S at all.

HM Revenue & Customs (HMRC) · SA103S
Section 4

Allowable expenses — boxes 11–20

Costs the business genuinely incurred, up to the date trading stopped. Only relevant if box 10.1 wasn't used.

The itemised boxes

Box 11 cost of goods for resale or used; box 12 car, van and travel costs after adjusting for private use; box 13 wages, salaries and staff costs; box 14 rent, rates, power and insurance; box 15 repairs and maintenance of property and equipment; box 16 accountancy, legal and other professional fees; box 17 interest and bank or credit card charges; box 18 phone, fax, stationery and other office costs; box 19 other allowable expenses — client entertaining is explicitly excluded here.

Box 20 — the combined-figure shortcut

One total expense figure straight into box 20 instead of itemising boxes 11–19 individually — available because turnover was under £90,000, which is also why SA103S was the right form to use in the first place.

Costs the business genuinely incurred, up to the date trading stopped. Only relevant if box 10.1 wasn't used.

HM Revenue & Customs (HMRC) · SA103S
Section 5

Net profit or loss, capital allowances and taxable profits — boxes 21–32

Page SES 2. The arithmetic that turns turnover and expenses into a taxable figure, plus the capital allowances that can reduce it further.

Box 21 or box 22 — net profit or net loss

Box 21 for a net profit, box 22 for a net loss — only one of the two is filled in, worked from box 9 plus box 10, minus box 20.

Capital allowances — boxes 23–26

Box 23 Annual Investment Allowance (100% relief on qualifying equipment, not cars); box 24 the allowance for a small unrelieved balance; box 24.1 the zero-emission car allowance; box 25 other capital allowances; box 25.1 Structures and Buildings Allowance; box 25.2 the Freeport and Investment Zones version; box 26 total balancing charges, where an asset is disposed of for more than its remaining tax value. None of these can be used if box 10.1's trading income allowance was claimed.

Boxes 27–30 — calculating taxable profits

Box 27 adds back goods or services taken for the owner's own use; box 28 is the net business profit for tax purposes (box 21 plus 26 plus 27, minus boxes 22–25.2 — or, if box 10.1 was used, box 21 plus 26 plus 27 minus box 10.1); box 29 is a loss brought forward from earlier years, capped at box 28; box 30 is any other business income not already in boxes 9 or 10.

Box 31 or box 32 — the total

Box 31 total taxable profits (box 28 plus 30, minus box 29), or box 32 net business loss for tax purposes — again, only one of the two is completed.

Page SES 2. The arithmetic that turns turnover and expenses into a taxable figure, plus the capital allowances that can reduce it further.

HM Revenue & Customs (HMRC) · SA103S
Section 6

Losses, Class 2/4 NICs and CIS deductions — boxes 33–38, and after you file

The last block, only fully relevant where box 32 shows a loss, or where an NIC election or CIS deduction applies — plus two procedural points from HMRC's own notes worth knowing before filing.

Boxes 33–35 — what happens to a loss

Box 33 sets a loss against other income for the same year; box 34 carries it back against earlier years' income or gains; box 35 is the total loss carried forward to set against future profits.

Box 36 — voluntary Class 2 National Insurance

Ticked to voluntarily pay Class 2 NICs where total 2025–26 profits across all self-employments were under £6,845 — it protects the State Pension and contributory benefit record for that year, and is easy to overlook on a low, part-year final return where it isn't obvious a partial year still carries an NI-record consequence.

Box 37 and 38 — Class 4 exemption and CIS

Box 37 is ticked if exempt from Class 4 NICs; box 38 records total CIS deductions taken from payments by contractors, for subcontractors only.

Provisional figures, and what not to send

If final figures aren't ready by the filing deadline, HMRC's notes allow provisional figures in boxes 1, 5, 9, 10, 21 or 22, 28, and 31 or 32 only — the rest is left blank, with an explanation in the SA100's 'Any other information' box, and final figures given later. Don't send receipts or accounts with the return unless HMRC specifically asks for them.

The last block, only fully relevant where box 32 shows a loss, or where an NIC election or CIS deduction applies — plus two procedural points from HMRC's own notes worth knowing before filing.

HM Revenue & Customs (HMRC) · SA103S

Many people file SA103S themselves — that is what this walkthrough is for. If the situation behind it has stopped being simple — beyond what a careful person can safely do alone — Signum, Valoren’s own specialist desk, can take it on, and we say so plainly: it starts with a free intake, and if you do not need us, we will tell you. Prefer an independent adviser? STEP and the Chartered Institute of Taxation both keep public member directories, and neither pays Valoren a referral fee.

FAQ

SA103S questions, answered.

SA103S is the short self-employment supplement to the main SA100 Self Assessment return. It reports turnover, expenses, capital allowances and net profit or loss for a sole trader's business with takings under £90,000.
Box 6Q asks whether the business ceased before 6 April 2026; if yes, box 6 asks for the final date of trading. For a personal representative, that's normally the date of death — not the tax year end, and not left blank.
Yes, in box 10.1 — but it's mutually exclusive with claiming any of the itemised expense boxes (11–20) or capital allowances (23–25.2). Claiming both is a common error, and the allowance can't be used to create or increase a loss.
No. If turnover was under £90,000, HMRC's own notes allow one combined figure straight into box 20 instead of itemising boxes 11–19 individually.
SA103S only applies where turnover was under £90,000 for the period — if it was higher, or would have been over a full year, the longer SA103F is the correct form instead.
No. SA103S covers the deceased's own trading income up to the date of death (or actual cessation, if earlier) only. Income the estate itself earns during administration is reported separately, not on SA103S.
Box 36 lets you voluntarily pay Class 2 National Insurance where total 2025–26 profits were under £6,845 — it protects the deceased's State Pension and contributory benefit record for that final year, and it's easy to overlook on a short, part-year return.
HMRC's notes allow provisional figures in boxes 1, 5, 9, 10, 21 or 22, 28, and 31 or 32 only — the rest is left blank, with an explanation given in the SA100's 'Any other information' box, followed by the final figures later.

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Where this fits

SA103S is one form. The file behind it is the rest.

Every figure on SA103S traces back to the deceased's own business paperwork — takings, invoices, expense receipts and asset purchases, up to the date trading stopped.

The Financial Accounts record holds exactly that, gathered once and ready to check against whichever box HMRC's SA100 letter is asking for.

HM Revenue & Customs (HMRC)44 fieldsFree to file — it's a supplement to SA100, not a separate submission with its own fee20 minutes with Valoren
Attaches to the main return

This is a supplementary page. It's filed together with the main Self Assessment return, not on its own.

The main return — SA100
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