Common mistakes
Never claimable — or take care
The costs people most often put through the books when they shouldn't, and the ones where the answer depends on the details.
Never claimable
| Entry | Why |
|---|---|
| #9 Ordinary commuting | Assuming the drive to your own unit counts because you need the van there. If the unit is where you normally work, that journey is commuting. |
| #10 Fines and penalty charges | Confusing a fine with a charge. The parking fee you pay at the meter while visiting a customer can be a business expense; the penalty notice for overstaying it can't. |
| #13 Everyday clothing | Claiming because "I'd never wear it otherwise". The test is whether it's ordinary clothing, not how you happen to use it. |
| #17 Carers and domestic help | Reasoning that "I couldn't work without it". It still counts as a personal cost. |
| #19 Goods or materials bought for private use | Leaving the whole receipt in the books. Take out the private part — or better, pay for it separately. |
| #20 Depreciation | Claiming depreciation and capital allowances. Depreciation is added back; the allowances replace it. |
| #26 Repaying loan or overdraft capital | Treating the whole instalment as an expense. Your loan statement shows how much is interest — that's the part you can claim. |
| #29 Client, supplier and customer entertaining and gifts | A branded bottle of wine or a hamper. Food and drink are out, even with your logo on. |
| #30 Political donations, gym membership and charity donations | A roofer's gym membership. However physical the work, fitness is personal. |
| #32 Training for a new, unrelated trade | Calling a career change "upskilling". The test is whether it builds on what you already do. |
| #39 Company formation and incorporation costs | Putting incorporation fees through your sole-trader accounts. |
Take care — it depends
| Entry | Answer | The key point |
|---|---|---|
| #3 Repairs and maintenance vs improvements | Partly | Repairs yes; improvements are capital. |
| #4 Working from home | Partly | Business share or flat rate — not both. |
| #5 Living at your business premises | Partly | Business share only — flat-rate deduction for living there. |
| #6 Structures and Buildings Allowance | Depends | Only for qualifying non-residential construction, with an allowance statement. |
| #24 Bad debts | Depends | Traditional accounting only. |
| #25 The cost of preparing your Self Assessment return | Partly | Business part only. |
| #34 First-year allowances | Depends | Mainly for new zero-emission cars and EV chargers. |
| #35 Writing-down allowances | Depends | Spread over years for items the AIA or FYAs don't cover. |
| #36 Business cars and capital allowances | Depends | Through capital allowances, not as an expense. |
| #40 Sole trader vs limited company — the same expense, treated differently | Depends | Different rules once you're a company. |
| #41 Cash basis vs traditional accounting | Depends | Cash basis is the default; it changes when costs count. |
| #42 The trading allowance vs claiming actual expenses | Depends | Allowance or actual expenses — not both. |
| #43 VAT and your expenses | Depends | Depends whether you're VAT-registered. |
Last checked: 10 November 2026.