Last reviewed: 30 May 2026
Quick summary
- This guide is for a side-business founder spending on stock, software, ads or equipment before the first sale and wondering whether those costs can reduce tax.
- Pin down when the trade started, whether costs are genuinely business-related, pre-trading expenditure, losses, evidence and whether the activity is commercial before asking for quotes or filing anything.
- Use the checklist and examples below to make the accountant conversation specific.
Topic hub: Side hustle tax hub
Direct answer
You should not treat this as a broad accountancy question. The answer depends on the specific records, dates, thresholds and decision in front of you. Start by pinning down when the trade started, whether costs are genuinely business-related, pre-trading expenditure, losses, evidence and whether the activity is commercial, then decide whether this is a DIY task, bookkeeping task or accountant judgement call.
What this guide is focusing on
Use this guide if you are a side-business founder spending on stock, software, ads or equipment before the first sale and wondering whether those costs can reduce tax. It focuses on the point where a generic article usually fails: the reader does not need a theory of accountancy, they need to know what to gather, what figure matters and what to ask before paying for advice.
What figure, record or decision should you pin down?
Pin down when the trade started, whether costs are genuinely business-related, pre-trading expenditure, losses, evidence and whether the activity is commercial. This is the decision model for the page. If those items are unclear, the accountant conversation should start with organising the facts rather than jumping straight to a filing answer.
Records to gather
- startup receipts
- date trading began
- stock or equipment list
- advertising spend
- business plan or sales activity evidence
Real examples for this situation
- A seller buys stock before launch and sells later in the tax year. Stock records need matching to sales.
- A freelancer pays for software before the first client. The business-use reason should be clear.
- A side project never launches. The answer may differ from a genuine trade that starts later.
Mistakes to avoid
- Claiming personal learning costs as business expenses without a trading link.
- Losing receipts before the first sale.
- Assuming no income means no records matter.
- Ignoring whether the activity is genuinely commercial.
Questions to ask an accountant
- When did the trade actually start?
- Which costs are pre-trading and business-related?
- Can a loss be claimed or carried forward?
- Should I use actual expenses or the trading allowance?
- What evidence shows this was a real business activity?
What an accountant will actually check
An accountant will look for evidence that the costs belong to a real trade rather than a personal idea or hobby. They will ask when the trade started, what the expenses were for, whether stock was later sold, whether software or equipment was used for the business, and whether any loss can be used or carried forward. The difference between learning, testing, preparing and trading can matter. Keep receipts, launch dates, first listings, first invoices and notes showing the commercial purpose.
How to evidence pre-sale costs
The cleaner your evidence, the easier this is. Keep supplier invoices, website subscriptions, course receipts, market research notes, product testing records and the date you first tried to sell. HMRC is more likely to accept costs where there is a visible business intention, not just a hobby that later becomes profitable.
For side businesses, also separate learning from trading. A course that teaches a broad personal skill can be harder to claim than software, stock, samples or domain costs bought for a specific business already being prepared. An accountant will usually look at the timeline before deciding whether the claim is sensible.
How to show the business had actually started
Startup cost claims are strongest when there is a clear business timeline. Keep evidence of the idea becoming a trade: domain purchases, supplier messages, product samples, market research, prototype work, sales pages, launch dates, stock purchases, platform setup and the date you first offered goods or services for sale. A receipt on its own says you spent money; the surrounding evidence explains why it was business expenditure.
Separate preparation, learning and private interest. Software for the business, stock, packaging, a website and professional costs may be easier to connect to the trade than a broad course, laptop or trip that also has personal value. Mixed-use costs need a sensible business proportion, not a blanket claim. If no sales have happened yet, the accountant will focus on whether there was a genuine commercial intention and when trading actually began.
Make a simple folder with costs before launch, costs after launch and costs you are unsure about. Add notes for anything paid personally, financed, refunded, partly private or bought before the business name existed. That is the fastest route to a sensible answer.
Extra accountant conversation point
If the business changes direction before the first sale, keep the old and new plans separate. Costs for a dropped idea may not fit neatly with the final trade. An accountant will usually ask whether the cost was incurred for the same trade that later began, whether it still benefits the business and whether the amount is capital or revenue in nature. A short timeline makes that judgement much easier.
Official guidance checked on 30 May 2026
Rules and thresholds can change. Check official guidance before important decisions.
Related guides
FAQs
What should I prepare first?
startup receipts, date trading began, stock or equipment list, advertising spend, business plan or sales activity evidence.
When should I speak to an accountant?
Speak to an accountant when the answer affects registration, VAT, MTD, company money, deadlines, records cleanup, a tax return or a decision you are not confident applying to your own facts.
What is the main mistake to avoid?
Claiming personal learning costs as business expenses without a trading link.
Pre-sales costs need dates and purpose
Startup costs are easier to discuss when you can show when the business idea became active, what each cost was for and whether the cost would be allowable if paid after trading started. Keep website, software, samples, market research, course, design and equipment invoices separately from personal spending. An accountant will usually ask whether the cost was genuinely for the trade and whether the business actually started.