The one rule
An expense is allowable if it is wholly and exclusively for the trade. That is the whole test. Where something is part business, part personal - your phone, say - you claim the business share and keep a note of how you worked it out.
The usual suspects
- Materials - pipe, plasterboard, cable, fixings, the lot
- Tools and equipment - including PPE and servicing
- Van costs - see the next section, there is a choice to make
- Insurance - public liability, tool cover, van insurance if claiming actual costs
- Phone and internet - the business share
- Accountant and professional fees
- Advertising - signwriting, flyers, online ads, the website
- Workshop or storage rent - and a fair share of home costs if you run the business from home
- Repairs - van repairs, tool servicing
- Subcontractor payments
- Bank charges and interest on business accounts and loans
The van: two ways, pick one
You can claim vehicle costs one of two ways, and you stick with your choice for as long as you keep the vehicle:
- Actual costs - fuel, insurance, MOT, repairs, plus capital allowances on the van itself. More paperwork, often worth more on an expensive van.
- Flat-rate mileage - 55p a mile for the first 10,000 business miles each tax year, 25p a mile after that (rates from April 2026). No fuel receipts to keep, but you need a mileage log: date, miles, where and why.
Either way the log or the receipts have to exist. A year of trips reconstructed from memory in January is the kind of claim that falls over when questioned.
Big kit and the £1m allowance
Vans, big tools and equipment are capital, not day-to-day expenses - but the Annual Investment Allowance gives 100% relief in the year you buy, on up to £1 million of qualifying spend. For most sole traders that means the van and the kit are fully relieved in the year of purchase.
Anything not covered goes into a pool and gets writing-down allowance each year. Worth knowing: the main pool rate dropped from 18% to 14% on 6 April 2026, and an accounting period straddling that date uses a blended rate.
What you can't claim
- Ordinary clothes - branded workwear and PPE yes, jeans and trainers no, even if you only wear them on site
- Home to your regular base - ordinary commuting is not claimable; travel between jobs and to suppliers is
- Entertaining - taking a customer for a pint is on you
- Fines and penalties - parking tickets included
- Materials the customer bought directly - you never incurred the cost
Proof beats memory
Photograph the receipt and log the expense the same day, with the right category on it. Under Making Tax Digital that is not just good practice - digital records of each transaction are the requirement. The habit that satisfies HMRC is the same habit that stops you under-claiming.