Help Centre · Partnership Returns (Beta) · 4 min read

SA800 trading income and expenses

The full SA800 income and expenses page: entering income and expense totals, the capital allowance pools, an optional breakdown of disallowables, and how the calculated boxes 3.65 and 3.73 drive the rest of the return.

Tax Optimiser Updated 11 Oct 2026
Beta feature — Partnership (SA800) returns are currently in beta and are switched on for one accountant firm at a time. To gain access for your firm, email support@taxoptimiser.co.uk and the team will enable it and help you get started.

The Trading Income step is the heart of the return: the SA800’s full income & expenses page (boxes 3.29–3.73). Tax Optimiser implements the full page for every partnership — it is also valid below the £90,000 three-line-accounts threshold, so there is one screen to learn. The form has an upper limit as well: where the combined annualised turnover from all of the partnership’s activities is more than £15 million, the SA800 asks for boxes 3.24 to 3.26 instead of this page, and for the partnership accounts and computations to be sent with the return.

Entering the figures

Every money box works the same way: type the amount (the £ sign, commas and spaces are all tolerated), and boxes that can go negative accept brackets — (1,500) means minus 1,500, matching how the form itself shows losses. Boxes with a grey tint are calculated and read-only; each one explains its own arithmetic underneath.

The Trading Income step: income boxes 3.29 and 3.50 and the expenses group, boxes 3.46 to 3.63

Income and expenses

  • Income: sales/business income (box 3.29) and other income/profits (3.50). Goods taken for personal use go in box 3.67 with the tax adjustments, not in box 3.29.
  • Expenses (boxes 3.46–3.63): entered at their full amounts including any disallowable part — cost of sales, subcontractor costs, employee costs, premises, repairs, admin, motor, travel, advertising, legal, bad debts, interest and finance charges, depreciation, and other expenses. The disallowable total is added back separately in box 3.66.

If “no trade or profession” is ticked on the Details step, this step and the Balance Sheet step show a notice and must be left empty — nothing on them is sent to HMRC.

Capital allowances and balancing charges

The capital allowances group: boxes 3.13A to 3.21 with the calculated totals 3.22 and 3.23

Each kind of allowance has its own box, as on the form: the Annual Investment Allowance (3.13A), the zero-emission goods vehicle allowance (3.14), main rate (3.14A) and special rate (3.16) allowances on equipment and cars, the zero-emission car allowance (3.16A), electric charge-points (3.18), structures and buildings (3.18A, and 3.18B for freeports and investment zones), and other capital allowances (3.20). Balancing charges go beside the pool they belong to (3.15A, 3.17) or in other balancing charges (3.21). Total capital allowances (3.22) and total balancing charges (3.23) are calculated.

Tax adjustments and the calculated result

The tax adjustments group with the calculated boxes 3.65 and 3.73
  • Net profit/(loss) (3.65) — calculated: gross profit (3.49) + other income (3.50) − total expenses (3.64).
  • Disallowable expenses (3.66) and goods taken for personal use (3.67) add back to profit. Depreciation (box 3.62) is never allowable, so box 3.66 must be at least the depreciation figure — the Review step tells you if it isn’t.
  • Deductions from net profit other than capital allowances (3.71).
  • Net business profit for tax purposes (3.73) — calculated: 3.65 + 3.66 + 3.67 + balancing charges (3.23) − capital allowances (3.22) − other deductions (3.71). This figure drives the whole return: a positive result becomes the taxable profit (3.83) and a negative one the allowable loss (3.84), and those are exactly what the Partnership Statement must allocate to the partners.
  • Adjustment on change of accounting basis (3.82) — carried to box 11A of the Partnership Statement.
  • CIS deductions (3.97) for tax deducted by contractors under the Construction Industry Scheme. It flows to box 24 of the Partnership Statement. (Box 3.98, for other tax taken off trading income, is still on the SA800 form, but HMRC’s online filing rules for 2025-26 say to leave it blank: include the amount in box 3.97 and give the details in the additional information box, 3.116, on the Details step.)
  • Net partnership charges paid (3.117) — charges not already deducted as an expense; carried to box 29 of the Partnership Statement.

Breaking down the disallowable expenses (optional)

The disallowable expenses by category group: boxes 3.30 to 3.43 with the calculated boxes 3.44 and 3.45

Box 3.66 is the one figure you must enter. If you want the return to show which expenses were disallowed, enter the amounts against their categories in boxes 3.30 to 3.43. Depreciation is always filed as box 3.44, and whatever is left of box 3.66 is filed as other expenses (3.45), shown calculated at the bottom of the group. The itemised amounts cannot add up to more than box 3.66.

Next: the balance sheet.

The short version

SA800 trading income and expenses — in brief

The Trading Income step implements the SA800's full income and expenses page, boxes 3.29 to 3.73, for partnerships with turnover up to the form's £15 million limit.

Expenses are entered at their full amounts; the disallowable part is added back in box 3.66 and can optionally be broken down by category.

Each capital allowance pool has its own box, with the totals 3.22 and 3.23 calculated.

Boxes 3.65 and 3.73 are calculated read-only, and 3.73 becomes the taxable profit (3.83) or allowable loss (3.84) that the Partnership Statement allocates.