US reader note. This page uses US English but discusses UK tax, VAT, CIS, or payment rules. Treat it as UK-focused educational content, not US legal, tax, or accounting advice. US requirements vary by federal, state, and local rules, so check with a qualified professional before applying anything to a US business.

Why tracking expenses matters

As a sole trader, you pay income tax and National Insurance on your profits -- that is, your income minus your allowable expenses. Every legitimate business expense you claim reduces the amount of profit HMRC taxes you on. Miss an expense and you pay more tax than you need to.

Many contractors overpay their tax bill simply because they do not keep proper records of what they spend. A 20 pound receipt for drill bits here, a 50 pound insurance payment there -- it adds up. Over a full tax year, unclaimed expenses can easily cost you hundreds or even thousands of pounds in unnecessary tax.

The rule is straightforward. An expense is allowable if it is incurred wholly and exclusively for business purposes. If something has both personal and business use, you can claim the business proportion.

Tools and equipment

Hand tools, power tools, ladders, scaffolding, work benches, PPE -- all of these are allowable expenses. If you buy a tool to do your work, you can claim it.

  • Hand tools -- spanners, screwdrivers, trowels, chisels, tape measures, and similar items.
  • Power tools -- drills, circular saws, angle grinders, nail guns, sanders, and so on.
  • PPE -- hard hats, safety goggles, ear defenders, dust masks, steel-toe boots, gloves, and hi-vis vests.
  • Ladders and access equipment -- step ladders, extension ladders, tower scaffolding.
  • Diagnostic and testing equipment -- multimeters, pipe cameras, laser levels, moisture meters.

For items costing less than 1,000 pounds, you can usually deduct the full cost in the year you buy them. For more expensive equipment, you may need to use capital allowances, which spread the cost over several years. The Annual Investment Allowance lets most sole traders deduct the full cost of qualifying equipment up to 1 million pounds per year.

Materials and supplies

Materials you purchase for a specific job are fully deductible. This includes timber, plaster, copper pipe, cable, fixings, adhesives, paint, tiles, cement -- anything you buy to complete customer work.

Stock you hold for general use is also claimable. Consumables like sandpaper, sealant, cleaning products, and waste bags all count. The key is that the materials are used for business, not personal projects.

Keep the receipts. HMRC can ask you to prove any expense you claim. A photo of a receipt stored on your phone is better than nothing, but a properly filed record with the date, supplier, amount, and what the purchase was for is what you really want.

Vehicle costs

Most contractors use a van or car to get to jobs and carry tools and materials. You have two options for claiming vehicle costs, and you need to pick one method per vehicle.

Option 1: Simplified mileage rates. You log your business miles and claim at HMRC's flat rate. Currently that is 45p per mile for the first 10,000 miles in a tax year, and 25p per mile after that. This covers fuel, insurance, repairs, and depreciation in one simple rate. You just need a mileage log showing the date, destination, purpose, and miles driven.

Option 2: Actual costs. You claim the real costs of running the vehicle -- fuel, insurance, road tax, MOT, servicing, repairs, breakdown cover, finance interest, and depreciation. You then work out what percentage of your total miles are for business and claim that proportion. If 80 percent of your driving is for work, you claim 80 percent of the costs.

Simplified mileage is easier to manage and works well if you do a lot of miles. Actual costs can work out better if your vehicle is cheap to run but you do not drive much. Once you choose a method for a vehicle, you cannot switch to the other method for that same vehicle in future years.

Insurance

Insurance premiums you pay for your trade are allowable business expenses. Common policies for contractors include:

  • Public liability insurance -- covers claims from third parties for injury or property damage. Most contractors carry this.
  • Professional indemnity insurance -- covers claims arising from your professional advice or design work. Particularly relevant for electricians, gas engineers, and architects.
  • Employers' liability insurance -- required by law if you employ anyone, even casually.
  • Tool and equipment insurance -- covers theft or damage to your tools, whether in your van or on site.
  • Van or vehicle insurance -- the business-use portion of your vehicle insurance is claimable (unless you use simplified mileage, which already includes it).

Phone and internet

If you use your personal phone for business calls, texts, and WhatsApp messages with customers, you can claim the business proportion of your phone bill. The same applies to your home internet if you use it for admin, email, or ordering materials.

The simplest approach is to estimate the percentage of business use. If roughly half your phone usage is for work, claim 50 percent of the bill. HMRC does not expect surgical precision, but the split should be reasonable and defensible.

If you have a separate business phone or a dedicated business broadband line, you can claim the full cost.

Clothing and uniforms

This is one area where HMRC draws a firm line. You can claim for:

  • Protective clothing -- steel-toe boots, hard hats, high-visibility jackets, overalls, waterproof trousers, and any clothing required for safety on site.
  • Branded uniforms -- polo shirts, jackets, or t-shirts with your business name or logo printed on them.

You cannot claim for ordinary clothes, even if you only wear them for work. A pair of jeans and a hoodie that you wear on site but could also wear to the shops is not a business expense. The clothing must be either protective in nature or clearly identifiable as a uniform.

Training and certifications

Courses and qualifications that update or maintain your existing skills are allowable. This includes:

  • Trade certifications -- Gas Safe registration, Part P electrical certification, CSCS cards, IPAF licenses, asbestos awareness.
  • CPD and refresher courses -- keeping your skills current in your existing trade.
  • Health and safety training -- first aid courses, working at height, manual handling.

There is an important distinction. Training that updates your existing skills is claimable. Training that gives you entirely new skills in a different trade is generally not. An electrician taking an advanced wiring course can claim it. The same electrician taking a plumbing course to start a new line of work probably cannot.

Other common allowable expenses

Contractors often forget about these, but they are all legitimate claims:

  • Accountancy and bookkeeping fees -- what you pay your accountant or bookkeeper.
  • Software and subscriptions -- invoicing tools, accounting software, trade apps.
  • Advertising and marketing -- business cards, flyers, website hosting, online ads, directory listings.
  • Trade memberships -- Federation of Master Builders, NICEIC, Checkatrade, TrustATrader, and similar.
  • Waste disposal -- skip hire, tip fees, and waste carrier license costs.
  • Postage and stationery -- stamps, envelopes, printer ink, notebooks.
  • Use of home as office -- if you do admin from home, you can claim a flat rate of 10 pounds per month for 25 or more hours of business use, or work out the actual proportion of household costs.

What you cannot claim

Not everything is deductible. HMRC specifically disallows:

  • Fines and penalties -- parking tickets, speeding fines, late filing penalties. These are never allowable, even if they happen during business hours.
  • Entertaining clients -- buying a customer lunch, drinks, or hospitality. Unlike some other countries, the UK does not allow business entertainment as a deduction.
  • Commuting costs -- travel between your home and a permanent workplace is not a business expense. Travel to temporary job sites is fine, but getting to your regular workshop or office is not.
  • Personal expenses -- anything that is not for business. A new phone case you also use on weekends, groceries, or personal subscriptions.
  • Clothing that is not protective or branded -- as covered above, ordinary workwear does not count.
Not sure? If you are uncertain whether an expense qualifies, the test is simple: was it incurred wholly and exclusively for business? If it has a personal element, can you reasonably separate the business portion? When in doubt, speak to an accountant. The cost of their advice is itself an allowable expense.

How good invoicing records help at tax time

Tracking expenses is only half the picture. You also need clean records of your income -- and that means proper invoices. When your invoices are numbered, dated, and stored in one place, matching them against bank payments at the end of the year is straightforward. When they are scattered across WhatsApp messages, scraps of paper, and half-remembered conversations, your Self Assessment becomes a headache.

Good records also protect you if HMRC opens an inquiry. They can ask to see your invoices and receipts going back several years. Having everything in order means an inquiry is a minor inconvenience rather than a major problem.

How WOPA helps contractors keep clean records

WOPA is built for contractors who want professional invoices without the admin. You send a WhatsApp message with the job details, the customer, and the amount. WOPA drafts the invoice, asks you to confirm, and emails a PDF to your customer. Every invoice is numbered, dated, and stored automatically.

At the end of the tax year, you have a complete record of every invoice you sent, every payment reminder that went out, and every payment that came in. Hand that to your accountant and your Self Assessment is half done before they even start.

No app to download. No spreadsheet to maintain. Just WhatsApp.

Join the waitlist to get US beta access when WOPA launches.