For self-employed associate dentists in the UK, knowing which expenses are allowable against your self-employed income is one of the most practical ways to reduce your tax bill. Claim the wrong items, or fail to keep proper records, and you risk an HMRC enquiry. Claim the right ones, and you keep more of what you earn.
This guide covers the main categories of associate dentist expenses for the 2025/26 tax year. It is written for self-employed associates working under a contract for services, not salaried associates on PAYE. If you are unsure about your employment status, read our guide on associate tax status and IR35 first.
The rules are specific. HMRC applies the "wholly and exclusively" test to every cost you claim. That means the expense must be incurred entirely for the purposes of your dental business, with no private benefit. If an item has mixed use, you must apportion the cost and only claim the business proportion.
Travel and Mileage: The Most Common Associate Expense
Travel is the single most claimed category of associate dentist expenses, and also the most frequently challenged by HMRC. The rules depend on where you are travelling from and to.
If you work at a single practice as your main place of work, travel between your home and that practice is ordinary commuting. It is not allowable. HMRC treats this as a personal cost, not a business expense, regardless of how far you live from the practice.
If you work at multiple practices, travel between them is allowable. For example, if you work at Practice A on Monday and Practice B on Tuesday, the journey from Practice A to Practice B is a deductible business journey. Travel from your home to the first practice of the day, or from the last practice back home, remains ordinary commuting and is not deductible.
For 2025/26, HMRC approved mileage rates for cars are 45p per mile for the first 10,000 business miles in a tax year, and 25p per mile thereafter. Motorcycles are 24p per mile, and bicycles 20p per mile. You can use these rates instead of tracking actual running costs (fuel, insurance, servicing, depreciation). You cannot claim both.
If you use your own car for business journeys, keep a mileage log. Record the date, start and end postcodes, purpose of the journey, and miles driven. HMRC can ask to see this at any time. A simple spreadsheet or a mileage tracking app is sufficient.
Locum dentists who travel to different practices each week face slightly different rules. See our locum dentist tax guide for specific advice on travel claims.
Equipment and Instruments: What Qualifies for Capital Allowances
Associate dentists often buy their own instruments, handpieces, loupes, and other clinical equipment. These are capital items, not day-to-day running costs. You claim tax relief through capital allowances, not as a straightforward expense.
For 2025/26, the Annual Investment Allowance (AIA) gives 100% tax relief on most plant and machinery purchases up to £1,000,000 per tax year. This covers dental chairs (if you own one), compressors, X-ray units, autoclaves, computers, practice management software, and surgical instruments. It does not cover cars, land, or buildings.
If you buy a set of loupes for £3,500, you can claim the full amount against your taxable income in the year of purchase, provided the equipment is used wholly for your dental business. If you also use the loupes for personal reasons (for example, a hobby), you must apportion the cost.
Smaller items such as gloves, masks, impression materials, and laboratory fees are revenue expenses. You claim them in full in the year you incur them, as long as they are used for your practice work. Keep invoices and receipts for everything.
One common mistake: associates sometimes claim the full cost of a laptop or tablet used partly for personal activities. HMRC expects a reasonable apportionment. If you use a laptop 70% for practice work (CPD, patient records, email) and 30% for personal use, you claim 70% of the cost. Be prepared to justify your split.
CPD, Courses, and Professional Subscriptions
Continuing Professional Development (CPD) is a mandatory requirement from the General Dental Council. The GDC requires 100 verifiable hours of CPD over a five-year cycle. The cost of courses, conferences, webinars, travel to attend them, and any associated accommodation are allowable expenses, provided the course maintains or improves your skills as a dentist.
This includes courses on clinical techniques, practice management, communication skills, and compliance. It does not include courses that are primarily for personal development or that lead to a qualification in an unrelated field.
Professional subscriptions to the GDC, BDA, and your dental defence organisation (MDU, Dental Protection, MDDUS) are also allowable. Indemnity insurance is a standard deductible cost for self-employed associates. If you are an employee, check your contract; some employers cover this directly.
If you attend a course abroad, the same rules apply. The course must be directly related to your dental work. A "dental conference" in a holiday destination will be scrutinised. Keep the course programme, your attendance certificate, and a note of the business purpose.
Practice Fees and Surgery Rent
Many self-employed associates pay a fee to the practice for the use of a surgery, equipment, nursing support, and reception services. This is often structured as a percentage of gross fees (the "fee split") or a fixed monthly rental. Both are allowable expenses against your associate income.
If you pay a fixed rental, keep the rental agreement and evidence of payment. If you pay a percentage split, your practice should provide a monthly statement showing gross fees, deductions, and the net amount paid to you. This statement is your primary evidence for HMRC.
Some associates also pay for materials directly (laboratory fees, impression materials, disposables). These are allowable as revenue expenses. If the practice deducts these from your fee split before paying you, you do not need to claim them separately; they are already reflected in your net income.
Home Office Expenses: A Limited Claim
If you do some of your practice administration from home (booking appointments, completing patient notes, CPD reading), you may be able to claim a proportion of your household costs. HMRC allows a simplified flat rate of £6 per week (£312 per year) for home office use if you work from home regularly. This covers heating, lighting, internet, and telephone use.
Alternatively, you can calculate the actual costs based on the number of rooms in your home and the proportion of time you use a room for business. This is more complex and requires detailed records. For most associates, the flat rate is simpler and sufficient.
You cannot claim mortgage interest, rent, or council tax as a home office expense if you are an associate. Those costs relate to your home as a whole, not to a specific business use. HMRC is strict on this point.
Clothing and Uniforms
Clinical scrubs, tunics, and protective footwear are allowable expenses if they are specific to your role as a dentist and not suitable for everyday wear. Ordinary clothing, even if worn only at work, is not allowable. HMRC draws a line between "protective clothing" (allowable) and "ordinary clothing" (not allowable).
If you buy a branded practice uniform with the practice logo, that is clearly business-specific and allowable. If you buy a plain white tunic that could be worn outside the practice, it is less clear. Keep receipts and be prepared to explain the business purpose.
What You Cannot Claim
Some costs are never allowable for a self-employed associate dentist. These include:
- Fines or penalties (parking tickets, speeding fines, HMRC late filing penalties)
- Childcare costs, even if you work late or attend evening CPD
- Gym memberships or health insurance (unless provided by the practice as part of your contract)
- Entertainment costs (meals with friends, social events)
- Political or charitable donations (unless directly related to your practice)
- Capital items used 100% privately (e.g., a family car)
Meals are a grey area. If you travel between practices and buy lunch, the cost of that meal is not allowable. HMRC considers it a personal living cost. The only exception is if you are away from your normal practice overnight, in which case reasonable subsistence costs may be claimed.
Record Keeping: The Non-Negotiable
HMRC can ask to see evidence for any expense you claim. The standard is "adequate records". For most associates, this means keeping:
- Receipts and invoices for all purchases over £10
- A mileage log for business journeys
- Bank statements showing payments to the practice and suppliers
- Practice statements showing fee splits and deductions
- Course attendance certificates and programmes
Digital records are acceptable. Scan paper receipts and store them in a cloud folder. Use accounting software such as FreeAgent, Xero, or QuickBooks if you want to automate the process. From 6 April 2026, Making Tax Digital for Income Tax will require sole traders and landlords with gross income over £50,000 to keep digital records and submit quarterly updates. Associates earning above that threshold should prepare now.
If you are unsure whether a specific cost is allowable, the safest approach is to ask a dental-specialist accountant before you claim it. The cost of professional advice is itself an allowable expense.
Common Mistakes Associates Make
Three errors appear repeatedly in HMRC enquiries against associate dentists.
First, claiming travel from home to a single practice as a business expense. As explained above, this is ordinary commuting. HMRC will disallow it and may charge interest and penalties.
Second, claiming the full cost of a mixed-use asset without apportionment. If you buy a laptop for £1,200 and use it 50% for practice work and 50% for personal use, you claim £600, not £1,200.
Third, failing to keep mileage logs. Without a log, HMRC can reject your entire travel claim. A log does not need to be complex. A simple spreadsheet with date, start/end postcodes, miles, and purpose is sufficient.
If HMRC opens an enquiry into your tax return, the first thing they ask for is your records. If you cannot produce them, they will estimate your tax liability, usually to your disadvantage. Good record keeping is your best defence.
Putting It All Together: A Worked Example
Consider Dr. Patel, a self-employed associate working at two practices. She earns £80,000 in gross fees. Her allowable expenses for 2025/26 might look like this:
- Travel between practices: 4,200 business miles at 45p = £1,890
- Instruments and loupes (AIA claim): £4,200
- CPD courses and travel: £1,100
- GDC, BDA, and indemnity subscriptions: £1,850
- Surgery rent and materials (deducted at source): £32,000
- Home office flat rate: £312
- Professional accountancy fees: £600
Total allowable expenses: £41,952. Her taxable profit is £80,000 minus £41,952 = £38,048. After the personal allowance of £12,570, she pays basic rate tax at 20% on £25,478, plus Class 4 National Insurance at 6% on the same amount. Her total tax bill is approximately £6,623, compared to over £13,000 if she had claimed nothing.
This example is illustrative. Your own figures will depend on your specific circumstances. Use our associate take-home calculator to model your own position.
Final Thoughts
Claiming the right associate dentist expenses is about knowing the rules and keeping good records. It is not about pushing the boundaries. HMRC has a dedicated team looking at healthcare professionals, and dental associates are a known area of focus.
If you are unsure about any aspect of your expenses, or if HMRC has opened an enquiry into your return, speak to a dental-specialist accountant who deals with associate tax day in, day out. The cost of advice is small compared to the cost of getting it wrong.
For a full breakdown of what you can and cannot claim, tailored to your specific role and working pattern, book a free practice health check with our team.