Use the short self employment pages (SA103S) if your turnover was below £90,000, or would have been for a full year, and your accounts need no special adjustments. Use the full pages (SA103F) if turnover was £90,000 or more, or if you need to adjust your accounts to the tax year, have adjustment income from changing accounting basis, need to adjust Class 4 profits, or were in HMRC’s Managing Serious Defaulters programme. The full pages also ask for an itemised expenses breakdown with disallowable amounts, detailed tax adjustments and, where your accounts have one, a balance sheet.

Who can use the short pages?

HMRC’s notes for the 2025 to 2026 short pages say to fill them in if your turnover was less than £90,000, or would have been if you had traded for a full year. GOV.UK describes the short version as being for people with relatively simple tax affairs whose turnover was below the VAT threshold. See our guide to the VAT registration threshold.

The short pages cover:

  • a description of the business, start and cessation dates, and the date the books are made up to;
  • whether you used traditional accounting rather than the cash basis;
  • turnover, other business income and the £1,000 trading income allowance;
  • expenses in broad categories, or a single total if turnover was below £90,000;
  • capital allowances, balancing charges and goods taken for own use;
  • losses, Class 2 and Class 4 National Insurance choices, and Construction Industry Scheme (CIS) deductions in box 38.

When must you use the full pages?

Both sets of notes list the same triggers for the full pages:

  • turnover of £90,000 or more, or turnover that would have reached that figure if you had traded for a full year;
  • a business that is more complicated;
  • an accounting period that ended before 31 March 2026, was not 12 months long, or did not end in the tax year, so that profits must be adjusted to the tax year;
  • adjustment income because you changed your accounting basis;
  • an adjustment to the profits chargeable to Class 4 National Insurance; or
  • being within the Managing Serious Defaulters (MSD) programme during the year.

The short notes add that a date in box 7 before 31 March 2026, unless you stopped trading, or after 5 April 2026 means you must use the full pages. In practice the accounting date is the most common reason a small business needs the long form. Since the tax year basis began, any year end outside 31 March to 5 April requires apportionment. See your first tax year as a sole trader for how that works.

What extra information do the full pages ask for?

Business and period details

Box 1 asks for the business name, unless it is your own name, and boxes 3 and 4 ask for the business address and postcode. Box 8 asks for the date your accounts start as well as the date they end. Box 14 is for someone who already reported this year’s profit on last year’s return, for example because a business started in 2024 to 2025 made its first accounts up to a date after 5 April 2025.

Itemised expenses with disallowable amounts

Boxes 17 to 30 break expenses into categories, from cost of goods and payments to construction subcontractors to wages, motor costs, premises, repairs, office costs, advertising, interest, financial charges, bad debts, professional fees and depreciation. Boxes 32 to 45 are a parallel column for the disallowable part of each, totalled in box 46. The notes say that if turnover is below £90,000 and you are not in the MSD programme, you can give a single total in box 31 instead of the breakdown.

Capital allowances and tax adjustments

Boxes 49 to 57 separate the annual investment allowance, 18% and 6% writing down allowances, zero emission goods vehicle allowance, structures and buildings allowance, electric charge point allowance and allowances on sale or cessation. Boxes 60 to 63 take you from accounts profit to tax profit, adding back disallowable items and goods for own use and deducting non taxable receipts. See capital allowances explained.

Adjusting to the tax year

Box 68 holds the adjustment where the accounting period ended before 31 March or was not 12 months long. Box 71 is for a change of accounting practice and box 72 for averaging by farmers, market gardeners and creators. Box 73.3 takes the share of any remaining transition profit from basis period reform.

Balance sheet

Boxes 83 to 99 cover assets, liabilities and the capital account, including capital introduced and drawings. The form says to fill these in if your business accounts include a balance sheet, and otherwise to go straight to box 100.

Other tax and National Insurance

Box 81 takes CIS deductions and box 82 any other tax taken off trading income. Box 102 takes adjustments to profits chargeable to Class 4 National Insurance, such as losses brought forward that have not been set against Class 4 profits.

How does the £90,000 test work for a part year?

The test looks at what turnover would have been over a full year, not just what you actually received.

Illustration only. Tom starts trading on 1 October 2025 and makes up accounts to 5 April 2026. His turnover for those six months is £50,000. Over a full year that is roughly £100,000, so he uses the full pages even though his actual turnover was well under £90,000. If he had instead taken £30,000 in the same six months, roughly £60,000 a year, the turnover test would not push him onto the full pages, although any of the other triggers still could.

The same full year test decides whether you can give a single expenses total on the full pages.

Do you need more than one set of pages?

Yes, in two situations. Each separate business needs its own self employment pages, even if one set of accounts covers them all. If more than one set of accounts ends in the tax year, for example after a change of accounting date, the full notes say to fill in boxes 1 to 65 and 83 to 99 on separate pages for each set of accounts. Boxes 68 to 82 and 100 to 103 then go on the pages for the most recent set. Our guide to Self Assessment supplementary pages explains how the other pages fit together.

What if your figures are not final?

Both versions allow provisional figures. On the short pages you fill in only boxes 1, 5, 9, 10, 21 or 22, 28 and 31 or 32. On the full pages you fill in boxes 1 to 16, 47 or 48, 64 or 65, 73 and 76 or 77, plus 73.3, 73.4 and 74 if they apply. In each case you must explain in the any other information box why you used provisional figures and when you expect to give final ones.

Does Making Tax Digital change this?

GOV.UK says sole traders and landlords whose qualifying income for 2024 to 2025 was over £50,000 should have started using Making Tax Digital for Income Tax from 6 April 2026. The thresholds then fall to £30,000 for 2025 to 2026 income, with use from 6 April 2027, and £20,000 for 2026 to 2027 income, with use from 6 April 2028. You still need to submit a Self Assessment return for the tax year before you start. The 2025 to 2026 return, due by 31 January 2027, is therefore still completed in the familiar way. See Making Tax Digital for Income Tax.

What mistakes come up most often?

  • Judging the threshold on part year turnover. A business that started part way through the year can be over the limit on a full year basis.
  • Using the short pages with a non standard year end. There is no box on the short pages to apportion profits to the tax year.
  • Leaving the disallowable column blank. If you include private or capital costs in boxes 17 to 30, the matching amounts must go in boxes 32 to 45.
  • Skipping the balance sheet when accounts have one. The boxes are optional only if your accounts have no balance sheet.
  • Entering turnover net of CIS deductions. Both versions want the gross amount, with deductions shown separately. See what counts as turnover.

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Sources

Reviewed by Christine Anderson, Broker, Solar Protect. Last reviewed 19 October 2026. Part of Accountapedia, the Solar Protect guide to UK tax and accounting. This page is general information, not personalised advice.