Running a business means spending money to make money. But here's the good news: many of those costs can reduce your tax bill. Understanding which expenses HMRC allows you to claim is essential for keeping more of your hard-earned profit.
Benjamin Franklin once said, "In this world, nothing is certain except death and taxes." While we can't avoid taxes entirely, we can make sure we're not paying more than necessary by claiming every allowable expense we're entitled to.
This guide breaks down the rules around allowable business expenses in the UK, covering everything from the "wholly and exclusively" test to simplified expenses, plus what you need to keep track of as key tax deadlines approach.
Allowable Business Expenses
What Makes an Expense Allowable?
HMRC has one core rule: expenses must be incurred "wholly and exclusively" for business purposes. This phrase appears throughout their guidance, and understanding it is crucial.
According to HMRC's Business Income Manual, the test is only satisfied if your sole purpose for incurring the expense is for your trade, profession or vocation. If there's any non-business purpose, even alongside business reasons, the expenditure fails the test.
For example, buying a suit you wear to client meetings sounds business-related. But because you could also wear it for personal occasions, it has dual purpose and isn't allowable. The same applies to everyday clothing, even if you only wear it at work.
The Three Key Points
Comparison Table
| Rule | What It Means |
|---|---|
| Sole Purpose | The expense must be only for business. Any personal benefit makes it non-allowable. |
| Incidental Benefit | If an expense is wholly for business but happens to provide a side benefit (like travelling to an exotic location for a project), that incidental benefit doesn't disallow it. |
| Apportionment | If you can identify a specific business portion of an expense (like using your mobile 30% for business calls), you can claim that portion. |
HMRC's official guide to self-employed expenses covers the basics in under three minutes.
Common Allowable Expense Categories
The GOV.UK expenses guidance lists the main categories you can claim. Here are the most common ones:
Office Costs
Stationery, postage, phone bills and printing costs all qualify, as long as they're for business use only. If you use your mobile for both personal and business calls, work out the business percentage and claim only that portion.
Travel Costs
Fuel, parking, train fares and bus tickets for business journeys are allowable. You cannot claim for your regular commute from home to a permanent workplace, but trips to meet clients, attend conferences or visit suppliers count.
For mileage, you can use simplified expenses: 45p per mile for the first 10,000 business miles, then 25p per mile after that.
Clothing
Only specialist clothing or uniforms that you wouldn't wear outside work qualify. Chef whites, high-vis jackets and branded uniforms are fine. Smart business attire is not.
Staff Costs
Salaries, employer National Insurance contributions, pension contributions and subcontractor fees are all allowable. Training costs for employees also count, as long as the training relates to their current role.
Stock and Raw Materials
Anything you buy to sell on or use in creating your product is allowable. This includes raw materials, packaging and goods for resale.
Legal and Financial Costs
Professional fees for accountants, solicitors and business advisors are allowable when incurred for business reasons. According to HMRC guidance, you can also claim:
- Professional indemnity insurance premiums
- Bank charges and overdraft fees
- Interest on business loans
- Leasing payments
You cannot claim for:
- Legal costs of buying property or machinery (claim these as capital allowances instead)
- Fines for breaking the law
- The cost of preparing your Self Assessment tax return
Business Premises Costs
Rent, business rates, heating, lighting, building insurance and repairs to business premises all qualify. If you work from home, you can claim a proportion of household costs like electricity, Council Tax and mortgage interest.
The key is finding a reasonable method of dividing costs. For example, if you use one room out of four exclusively as an office, you can claim 25% of eligible household bills. If you only work from home two days a week, reduce that proportionally.
Marketing and Advertising
Website costs, online advertising, business cards and promotional materials are all allowable. Subscriptions to trade publications and professional memberships that help you run your business also count.
Simplified Expenses: The Easy Option
Rather than tracking every receipt and working out business percentages, you can use simplified expenses for certain costs. This means claiming a flat rate instead of actual costs.
Working from Home
You can only use this if you work 25 hours or more per month from home. The rates are:
Comparison Table
| Hours per Month | Flat Rate |
|---|---|
| 25 to 50 | £10 |
| 51 to 100 | £18 |
| 101 or more | £26 |
For example, if you worked 60 hours from home for eight months and 40 hours for four months, you'd claim:
8 months × £18 = £144
4 months × £10 = £40
Total claim = £184
According to GOV.UK, the flat rate doesn't include telephone or internet expenses. You can still claim the business proportion of these separately.
Vehicle Costs
For cars and vans, simplified expenses are:
- 45p per mile for the first 10,000 business miles
- 25p per mile thereafter
This covers fuel, insurance, repairs, servicing and vehicle depreciation. You cannot claim additional vehicle costs if you use this method.
What You Cannot Claim
Some expenses never qualify, no matter how business-related they might seem:
- Personal living costs (food, accommodation, holidays)
- Clothing for everyday wear
- Entertaining clients (though staff entertaining is allowable)
- Fines and penalties
- Charitable donations (though they may qualify for other tax reliefs)
- Repayments of loans or finance arrangements (though interest on these can be allowable)
If you're using the £1,000 trading allowance, you cannot claim any expenses at all. The allowance replaces your expense claims.
Limited Companies vs Self-Employed
The rules differ slightly depending on your business structure.
Self-employed individuals (sole traders and business partners) follow the "wholly and exclusively" test described above. They claim expenses when calculating their taxable profit on their Self Assessment tax return.
Limited company directors are technically employees of their company. The company can claim expenses under Corporation Tax rules, which are similar but not identical. Directors can also claim certain employee expenses or be reimbursed by the company for business costs.
For directors and employees, expenses must be incurred "wholly and exclusively in the performance of the duties of the employment," according to HMRC's Employment Income Manual. The test is slightly stricter than for self-employed traders.
This HMRC video explains the "wholly and exclusively" rule for landlords, but the principle applies across all business types.
Record Keeping Requirements
HMRC expects you to keep records and proof of your business costs. You'll need these to complete your Self Assessment tax return, and HMRC may ask to see them during an enquiry.
Keep:
- Receipts and invoices
- Bank statements showing business transactions
- Mileage logs for vehicle expenses
- Records of working-from-home hours if using simplified expenses
- Records showing how you split dual-use expenses
Most businesses must keep records for at least five years from the 31 January submission deadline of the relevant tax year.
Key Deadlines for 2026
As of 22 February 2026, here are the crucial dates to remember:
6 April 2026: If your turnover from self-employment and property is above £50,000, you must start keeping digital records using Making Tax Digital (MTD) for Income Tax compatible software.
7 August 2026: Deadline to send your first quarterly update (for those using MTD).
7 November 2026: Deadline to send your second quarterly update.
31 January 2027: Deadline to submit your Self Assessment tax return for the 2025/26 tax year (the traditional way, for the last time if you're in MTD scope).
The Making Tax Digital timeline shows that from April 2026, many businesses will need to submit quarterly updates digitally, fundamentally changing how expenses are recorded and reported.
Why Industry-Specific Knowledge Matters
The general rules apply across all sectors, but knowing which expenses are standard in your industry can make a significant difference to your tax position.
A graphic designer might claim software subscriptions and Adobe Creative Cloud licenses. A builder claims tool purchases and van expenses. A consultant claims professional development courses and client entertainment costs (within limits). A property landlord focuses on maintenance, letting agent fees and gas safety certificates.
An accountant who understands your specific industry will spot allowable expenses you might miss. They'll know which costs HMRC typically questions in your sector and how to document them properly. They'll also understand the nuances of simplified expenses versus actual costs for your situation.
If you're claiming substantial home office expenses, vehicle costs or equipment purchases, professional advice tailored to your business type ensures you're claiming correctly without triggering unnecessary HMRC queries.
Finding the Right Professional Support
Getting your expenses right isn't just about following rules. It's about understanding how those rules apply to your unique business situation, your industry norms and your growth plans.
An accountant who has worked with similar businesses in your sector will recognise patterns, spot opportunities and help you structure your expenses in the most tax-efficient way. They'll ensure you're not leaving money on the table through under-claiming, nor attracting scrutiny through over-claiming.
With Making Tax Digital changing how expenses are reported from April 2026, having an accountant who understands both the technology and your business becomes even more valuable. They can help you choose compatible software, set up efficient processes and ensure your quarterly updates accurately reflect your actual business activity.
Rather than spending hours searching for an accountant and hoping they understand your industry, let accountantfinder.ai match you with a qualified professional who has proven experience with businesses like yours. Answer a few questions about your business structure, industry and needs, and you'll be connected with accountants who genuinely understand your sector.
The right accountant doesn't just help you claim expenses correctly. They become a strategic partner in your business success, offering advice that goes far beyond basic compliance.