Can You Claim Mileage as a Self-Employed Associate Dentist?

The short answer is yes, but only for certain journeys. If you are a self-employed associate dentist working across multiple dental practices, you can claim tax relief on travel between those practices. However, the journey from your home to your main practice is not allowable. This distinction trips up many dentists and can lead to unnecessary tax bills if you get it wrong.

HMRC draws a clear line between "ordinary commuting" (home to a permanent workplace) and "business travel" (travel between workplaces or to a temporary workplace). For a self-employed associate dentist, each practice you work at is a separate workplace. Travel between them is business travel. Travel from home to your first practice of the day is commuting, unless that practice is a temporary workplace under HMRC's definition.

This article explains the rules in plain English, with real examples and the current mileage rates for 2025/26. We also cover what records you need to keep and how to claim the relief on your Self Assessment tax return.

HMRC Rules on Mileage for Self-Employed Associate Dentists

HMRC's guidance on travel expenses for the self-employed is set out in the Business Income Manual (BIM). The key principle is that travel costs are allowable if they are incurred "wholly and exclusively" for the purposes of the trade. For a self-employed associate dentist, that means travel between different workplaces is allowable, but ordinary commuting is not.

HMRC defines a "permanent workplace" as a place you attend regularly, for more than 24 months, or where you spend 40% or more of your working time. For most associate dentists, each practice you work at on a regular schedule (e.g., every Tuesday and Thursday) is a permanent workplace. Travel from home to that practice is commuting.

However, if you work at a practice only occasionally, or for a short-term contract, it may qualify as a "temporary workplace". In that case, travel from home directly to that practice is allowable. This is a common scenario for locum dentists, but it can also apply to associates covering a colleague's list for a few months.

What Counts as a Qualifying Journey?

For a self-employed associate dentist, the following journeys are typically allowable:

  • Travel from your home to a temporary workplace (e.g., a practice you cover for three months)
  • Travel between two practices on the same day (e.g., from Practice A to Practice B)
  • Travel from a practice to a training course or CPD event that is directly related to your work
  • Travel from a practice to a dental laboratory or supplier for work-related purposes

The following journeys are not allowable:

  • Travel from home to your main permanent practice
  • Travel from home to a practice you attend regularly (even if it is not your "main" practice)
  • Travel from home to a practice where you have a fixed schedule and no end date

Mileage Allowance Rates for 2025/26

HMRC publishes approved mileage allowance payments (AMAPs) for business travel in private vehicles. For 2025/26, the rates are:

  • Cars and vans: 45p per mile for the first 10,000 business miles in the tax year, then 25p per mile thereafter
  • Motorcycles: 24p per mile
  • Bicycles: 20p per mile

These rates are designed to cover both fuel and the running costs of your vehicle (insurance, maintenance, depreciation). You cannot claim separately for those costs if you use the mileage rate. Alternatively, you can claim the actual costs of running your vehicle (fuel, insurance, repairs, etc.) apportioned for business use. For most associate dentists, the mileage rate is simpler and more generous, especially if you have a fuel-efficient car.

If you use an electric car, the 45p/25p rates still apply. There is no separate lower rate for electric vehicles, despite some misconceptions. HMRC confirmed this in their 2024/25 guidance.

Worked Examples for Associate Dentists

Example 1: Two Practices, Regular Schedule

Sarah is a self-employed associate dentist. She works at Practice A on Mondays and Wednesdays, and at Practice B on Tuesdays and Thursdays. Both practices are permanent workplaces. She drives 15 miles from home to Practice A, then 20 miles from Practice A to Practice B on Wednesdays when she has a split day.

Her allowable mileage claim:

  • Home to Practice A: Not allowable (commuting)
  • Practice A to Practice B: Allowable (20 miles each way, 40 miles total per Wednesday)
  • Home to Practice B: Not allowable (commuting)

If Sarah does this for 48 weeks of the year, she can claim 40 miles x 48 weeks = 1,920 business miles. At 45p per mile, that is £864 in tax relief. As a higher-rate taxpayer (40%), she saves £345.60 in income tax and £115.20 in Class 4 NI, for a total saving of £460.80.

Example 2: Three Practices, One Temporary

James is an associate dentist at Practice X (his main practice, 3 days a week). He also covers a colleague's maternity leave at Practice Y for 6 months (2 days a week). Practice Y is 25 miles from his home. He also does one day a month at Practice Z, a private clinic 30 miles away.

His allowable mileage claim:

  • Home to Practice X: Not allowable (permanent workplace)
  • Home to Practice Y: Allowable (temporary workplace, less than 24 months and not regular long-term)
  • Home to Practice Z: Allowable (temporary workplace, occasional attendance)
  • Practice X to Practice Y on a split day: Allowable

James can claim 25 miles x 2 days x 26 weeks = 1,300 miles for Practice Y, plus 30 miles x 12 months = 360 miles for Practice Z. Total: 1,660 miles at 45p = £747. His tax saving as a higher-rate taxpayer is approximately £298.80.

How to Claim Mileage on Your Self Assessment

You claim mileage as a business expense on your Self Assessment tax return. The relevant box is in the "Self-employment" section (pages SA103S or SA103F). You enter the total allowable mileage expenses in the "Travel and subsistence" box. You do not need to submit a separate form for AMAPs, but you must keep records to support your claim.

If you use the mileage rate, you simply multiply your business miles by the appropriate rate and enter the total. If you use actual costs, you need to calculate the proportion of total vehicle costs that relate to business use (e.g., if you drive 10,000 miles total and 4,000 are business, you claim 40% of your fuel, insurance, servicing, etc.).

Most associate dentists find the mileage rate simpler and more tax-efficient. However, if you have a very expensive car with high running costs, the actual cost method might give a larger deduction. It is worth running both calculations to see which is better for your situation.

Records You Must Keep

HMRC can ask to see evidence of your business mileage. You should keep a mileage log for each vehicle you use. The log should record:

  • Date of each journey
  • Start and end addresses (including practice names)
  • Purpose of the journey (e.g., "travel from Practice A to Practice B for afternoon list")
  • Mileage for each journey
  • Total business and private miles for the vehicle

You can keep this log in a notebook, a spreadsheet, or using a mileage-tracking app. HMRC accepts digital records. The key is that the log is created at or near the time of the journey, not reconstructed months later. A contemporaneous record carries more weight if HMRC enquires into your return.

If you use the actual cost method, you also need to keep receipts for fuel, insurance, servicing, repairs, and any other vehicle costs. For the mileage rate, you only need the log and a record of the total business miles.

Common Mistakes Associate Dentists Make

Three errors come up repeatedly in our work with associate dentists.

Mistake 1: Claiming home-to-practice mileage as a business expense. Even if you work at multiple practices, the journey from your home to your first practice of the day is almost always commuting. Only if that practice is a temporary workplace (less than 24 months, irregular attendance) can you claim it.

Mistake 2: Not separating business and private mileage. You cannot claim mileage for personal journeys, even if they happen on the same day as a business trip. If you drive from Practice B to the supermarket on your way home, that leg is private.

Mistake 3: Using the wrong rate for electric cars. Some dentists think electric cars have a lower rate. They do not. The 45p/25p rates apply to all cars, including electric. However, if you charge your electric car at home, you cannot claim the electricity cost separately if you use the mileage rate. The 45p rate is meant to cover all running costs.

What About Salaried Associate Dentists?

If you are a salaried associate dentist (employed under a contract of service, not self-employed), the rules are different. Employees can claim mileage relief on business travel, but the definition of "business travel" is narrower. For employees, travel from home to a permanent workplace is never allowable. Travel between workplaces is allowable only if the journey is for a work-related purpose and the employee is not simply commuting between two permanent workplaces.

Salaried associates should check their employment contract. Some practices reimburse mileage at HMRC's approved rates. If they do, the reimbursement is tax-free up to the AMAP rates. If the practice pays less than the AMAP rate, the employee can claim tax relief on the difference. If the practice pays more, the excess is taxable as earnings.

For most salaried associates, the simplest approach is to agree with your practice a clear policy on travel reimbursement. If you are unsure, speak to a dental-specialist accountant who can review your specific arrangement.

Mileage and the NHS Pension Scheme

One point that catches out associate dentists: mileage expenses do not affect your NHS Pension contributions. Your pensionable earnings are based on your NHS fee income (UDAs, private fees, etc.), not your net profit after expenses. So claiming mileage does not reduce your pensionable earnings or your future pension benefits. This is a common concern, but it is not an issue for self-employed associates.

However, if you are a salaried associate, your pensionable earnings are your salary. Mileage reimbursements are not pensionable, so they do not affect your pension contributions either way.

When to Use a Dental-Specialist Accountant

Mileage claims are straightforward for most associate dentists, but the rules become more complex if you have multiple practices, use a limited company, or have a mix of self-employed and employed income. A dental-specialist accountant can help you structure your travel claims correctly and avoid HMRC enquiries.

At Dental Finance Partners, we work with hundreds of associate dentists across the UK. We can review your mileage log, calculate your claim, and ensure it is fully compliant with HMRC rules. We also help with associate tax planning, including our Associate Tax Survival Guide, which covers mileage, expenses, and tax-saving strategies in detail.

If you are a principal or practice owner, you may also want to read our guide on practice accounting to understand how mileage and travel expenses affect your practice's profitability.

Final Checklist for Associate Dentists Claiming Mileage

  • Identify each practice as permanent or temporary based on HMRC's definitions
  • Keep a contemporaneous mileage log with dates, addresses, and purposes
  • Use the 45p/25p mileage rate or calculate actual costs (choose the more beneficial method)
  • Claim only business travel between practices, not home-to-practice commuting
  • Include the claim in your Self Assessment tax return under "Travel and subsistence"
  • Review your claim annually, especially if your practice schedule changes

If you are unsure about any aspect of your mileage claim, contact our team for a free initial discussion. We are dental-specialist accountants who understand the unique tax position of associate dentists in the UK.