SA103 expense categories — where each cost goes

Updated: 14/07/2026 · 6 min read

When you file Self Assessment as self-employed, expenses are reported on the SA103 pages in numbered boxes. Putting costs in the right box keeps your return consistent and audit-friendly. Here is the practical mapping for the boxes most sole traders use.

The main SA103F expense boxes

Box 17 — Cost of goods bought for re-sale or goods used (materials, stock)
Box 19 — Wages, salaries and other staff costs
Box 20 — Car, van and travel expenses
Box 21 — Rent, rates, power and insurance costs
Box 23 — Office costs: phone, stationery, software
Box 24 — Advertising and business entertainment costs
Box 28 — Accountancy, legal and other professional fees
Box 30 — Other allowable business expenses

Common mappings in practice

Trade materials and tools consumed on jobs → box 17
Fuel, insurance, MOT, repairs (or mileage claim) → box 20
Business share of home utilities, premises insurance → box 21
Mobile phone, broadband, invoice software → box 23
Accountant’s fee for your return → box 28
Bank charges, small sundries that fit nowhere else → box 30

Why the right box matters

The totals drive HMRC’s risk profiling: a builder with zero cost of goods but huge "other expenses" looks odd. Consistent categorisation year to year also makes an enquiry far less painful — every number traces to receipts in a known bucket.

Under £90,000 turnover: one total is allowed — but…

If your turnover is below the VAT threshold you may report a single total of expenses instead of the breakdown. Many accountants still prefer the breakdown — it is clearer evidence and better analytics for you. If your records are categorised automatically, the breakdown costs you nothing.

Automate the mapping

Reclaim Day assigns each document a category (Materials & Tools, Travel & Transport, Office & Supplies…) and the export includes the SA103 box number and Sage nominal code for every line — so your accountant, or you, can lift the totals straight into the return.

Every receipt captured, categorised and audit-ready.

Snap a photo or forward the email — Reclaim Day reads the vendor, amounts, VAT and date for you.

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Frequently asked questions

Which SA103 box do materials go in?+

Box 17 — cost of goods bought for re-sale or goods used. That includes trade materials consumed on jobs.

Where do van costs go on SA103?+

Box 20 — car, van and travel expenses, whether you claim actual costs or the mileage rate.

Do I have to break expenses down by box?+

Below the VAT threshold you can report one total, but the breakdown is better evidence, better analytics, and effortless if your records are categorised automatically.

What goes in box 30 (other expenses)?+

Allowable costs that fit no other box — e.g. bank charges or small sundries. It should be the smallest box, not the biggest.

This guide is general information, not tax advice. Rules and figures change — check gov.uk (HMRC) for current rates, and speak to an accountant about your situation.