Why Allowable Expenses Matter So Much

Every pound you claim as a legitimate business expense reduces the profit HMRC taxes you on. It sounds obvious, but plenty of sole traders quietly overpay because they assume something "isn't worth claiming" or worry it will trigger an investigation. In practice, claiming what you're entitled to — with clean records to back it up — is exactly what HMRC expects you to do.

If you're a sole trader, you'll usually report your income through Self Assessment unless trading income falls below the £1,000 trading allowance. Either way, the expenses you deduct lower your taxable profit, not your turnover. A £200 cost doesn't save you £200 in tax; it saves you £200 multiplied by your marginal rate. At the basic rate, that's around £40 back in your pocket. Small numbers, repeated monthly, add up to real money over a year.

The Golden Rule: Wholly and Exclusively

Nearly every question about expenses comes back to one phrase. A cost must be incurred wholly and exclusively for the purposes of your trade. If it's partly personal, either it isn't allowable at all, or you need to apportion it fairly and claim only the business share.

There's also a distinction many people miss: you can only deduct revenue expenses — day-to-day running costs — from your profit in the year you incur them. Capital items, such as equipment, vehicles or significant fixtures, are handled differently through capital allowances. Getting this wrong is one of the most common reasons for a nasty surprise.

Everyday Costs You Can Usually Claim

Most sole traders will recognise their own spending in this list. As long as the cost is genuinely for the business and you hold evidence, it's normally fine:

• Office and admin: stationery, printer ink, postage, software subscriptions, cloud storage, accountancy and bookkeeping fees, bank charges on a business account.
• Phone and internet: claim the business proportion. If your broadband is 70% business, claim 70% — and be able to explain how you reached that figure.
• Insurance: professional indemnity, public liability, tools cover, and relevant professional body memberships.
• Marketing: website hosting, domain names, advertising, printed materials, paid social posts.
• Training: courses that update or maintain skills you already use in the business. Training that qualifies you for a brand new trade generally isn't allowable.
• Protective clothing and uniforms: logoed workwear and safety gear, including cleaning and repairs. Everyday clothing you'd wear anyway is not claimable, even if you only ever wear it to work.
• Business travel and subsistence: train fares, parking, congestion charges, and reasonable meals while travelling for work away from your normal base.

Working From Home and Vehicles

If you run the business from home, you can claim a share of household running costs — heating, electricity, water, council tax and broadband — based on how much and how long you use each room for work. Keep the method simple and consistent, and document it. HMRC also offers a flat rate of £6 a week for homeworking, which many sole traders use because it needs no receipts and no apportionment sums. You can use the flat rate or actual costs, but not both at once for the same period.

Cars, vans and motorcycles come with two main routes. You can use simplified mileage rates — currently 45p per mile for the first 10,000 business miles in a tax year, then 25p per mile thereafter, with 24p per mile for motorcycles. This covers fuel, servicing, insurance and depreciation, but not parking or train fares. The alternative is the actual costs method, where you record all running costs and claim the business proportion, plus capital allowances on the vehicle itself. Pick the method that suits your mileage and stick with it while using that vehicle.

What You Can't Claim

Some costs trip people up year after year. You can't deduct:

• Personal spending, however convenient it is to put through the business.
• Ordinary commuting between home and a permanent workplace.
• Fines, penalties and most legal costs arising from them.
• Client entertaining — a common sting for anyone used to how limited companies and employees are treated.
• Drawings. Taking money out of the business isn't an expense; it's your income.

Gifts to clients are a grey area and usually only work if they're branded, cost under £50 per recipient per year, and aren't food, drink or tobacco.

Keep the Evidence and Keep It Separate

The single best habit you can build is a clean separation between business and personal money. A dedicated business bank account — even a basic second current account — makes your bookkeeping dramatically easier and your claims far more defensible.

For every expense, keep the receipt, invoice or bank record. Digital copies are fine and arguably better: photograph paper receipts as you go, or forward emailed invoices straight to a folder. Note the date, the amount, who you paid and what it was for. If something is partly personal, write down the split you've used while it's fresh in your mind.

HMRC generally expects records to be kept for at least five years after the 31 January submission deadline for the relevant tax year. If you're ever asked to explain a figure, a tidy folder of dated receipts turns a stressful enquiry into a short email. Do the small admin each month and the tax return becomes a much calmer afternoon.

When you're unsure about a specific cost, the test is simple: was it spent purely to earn your business income, and can you prove it? If the answer is yes, claim it.