Allowable expense evidence for sole traders

An expense claim needs evidence of the payment and its business purpose, with private use separated where required. A receipt proves a purchase occurred but does not, by itself, establish that the full cost is allowable for a sole trader.

Group costs by activity and flag equipment, shared household bills and unusual purchases. Accounting treatment and tax deductibility can differ, particularly where capital items or mixed use are involved.

Identify the purpose behind the document

For each expense category, ask what was bought, how it supported the trade and who used it. A retailer's receipt may contain several items with different purposes. Keep the original document and a brief explanation of the business element rather than editing out personal purchases. The person who incurred the cost is usually best placed to provide that context promptly.

HMRC's self-employed expense guidance distinguishes allowable business costs, private spending and the relevance of the accounting method. ^[1] Use that framework to identify questions for review. Do not assume an expense becomes deductible because it appears in a business account, or that a large purchase must have the same treatment as a recurring subscription from the same supplier.

Build a record that supports mixed-use costs

Telephone, internet, vehicle and household costs can contain both business and private use. Describe the actual arrangement and retain the basis of the proposed allocation. Relevant evidence might include usage records, working patterns or identifiable components of a bill. An allocation should reflect the circumstances, not a round percentage selected because it produces an attractive claim.

Review the basis when the facts change. A trader who takes separate business premises or stops using a vehicle for work should not continue the previous allocation automatically. Keep the old calculation for the period it covered and document the new approach. Use Working from home as a sole trader for homeworking costs and Business mileage records for self-employed people for vehicle records, where simplified methods and actual costs need separate consideration.

Distinguish payment evidence from purchase evidence

A bank or card statement can show that money moved, but may not explain the goods or services supplied. Request a replacement invoice or receipt from the supplier where possible. Connect it to the payment reference and record any credit, refund or later adjustment. This prevents the same purchase being claimed from both a card entry and a separately submitted invoice.

Where a document cannot be recovered, explain the missing evidence honestly and discuss the available support with the accountant. Do not manufacture a receipt or backdate a note to make it look contemporaneous. A dated reconstruction can identify what is known and what remains uncertain, allowing the preparer to assess the proposed treatment on a transparent basis.

Review unusual and bundled expenditure

Flag equipment, training, professional fees, pre-trading purchases and costs linked to acquiring or improving an asset. Supply the agreement or itemised invoice and describe the intended use. These transactions often need more analysis than ordinary stationery or routine service charges. The fact that a purchase helped the business does not settle every timing or relief question.

For a bundled package, ask the supplier to distinguish equipment, support, installation and financing where relevant. Keep the breakdown with the bookkeeping entry. If an item is partly refunded or replaced, update the record so the final claim reflects the actual transaction. Review any overlap with a simplified method before including the same underlying cost elsewhere in the accounts.

Make expense review part of the routine

Set a regular submission date and give each unresolved item an owner. A monthly review can focus on missing documents, unclear business purpose and possible duplicates. Keep factual questions separate from tax judgements: the trader confirms what happened, while the adviser assesses the applicable treatment. This is more effective than asking the accountant to infer business purpose from a year's worth of unexplained bank descriptions.

For Self-employed expense review, provide an expense schedule linked to evidence, the accounting method and a list of mixed-use or unusual items. Ask for specific decisions and the records needed to support them in future. Preserve the final adjustments so they can be entered into the live bookkeeping system and understood at the next year end.

Before approving the return, compare the expense analysis with known changes in the business. A substantial fall in costs may reflect improved efficiency, but it could also mean a supplier account or card statement was omitted. Investigate material changes through the underlying transactions. The objective is a complete and accurate result, with neither unsupported deductions nor legitimate expenditure lost through poor record organisation.

Illustrative scenario

A photographer buys a laptop used for client work and family tasks. They retain the invoice and a reasonable explanation of business use, then ask how the chosen accounting basis treats the purchase.

Preparation checklist

• Keep the invoice
• Describe the business purpose
• Identify private use
• Flag equipment and unusual costs