Can a self-employed associate dentist claim mileage across multiple practices?
If you are a self-employed associate dentist splitting your week across more than one practice, mileage is one of the more valuable expenses you can claim, but only for the right journeys. Travel between practices on the same day is normally business travel and is allowable. The drive from home to a single regular practice is ordinary commuting and is not. Getting that line right is the whole game, because the wrong claims are exactly what an HMRC enquiry looks for.
This article is the mileage deep dive for associates working across several sites. It covers the 2026/27 rates, what counts as a qualifying journey, the home-to-first-practice trap, the choice between the mileage method and actual costs, and the records you must keep. For the wider picture of everything an associate can deduct, see our guide to allowable expenses for associate dentists, and for Self Assessment as a whole see the associate dentist tax guide. This page goes deeper on travel than either of those.
The commuting trap: home to your first practice
HMRC draws a hard line between ordinary commuting and business travel. Ordinary commuting is the journey between your home and a place you attend regularly to do your work, and it is never deductible, however far you drive and however inconvenient the route. Business travel is travel you make in the course of the work itself, which for an associate mainly means travel between workplaces.
The trap is that each practice you attend on a settled, ongoing basis is a regular workplace. So the drive from home to your first practice of the day is commuting, even if you only work there two days a week, and even if it is not your "main" practice. The fact that you happen to work across several sites does not turn the home-to-practice leg into business travel. What it does do is create allowable journeys in between.
An associate working across several practices therefore has a genuinely stronger case for inter-practice travel being business mileage than a dentist sitting at one chair all week, but the strength of that case lives or dies on the record-keeping. A clear mileage log that shows you drove from one practice to another on the same day is persuasive. A round figure typed in at the year end is not.
What counts as a qualifying journey
For a self-employed associate dentist, the journeys that are normally allowable are:
- Travel between two practices on the same working day, in either direction
- Travel from your home or a practice to a genuinely temporary workplace, such as a practice you are covering for a short, time-limited spell
- Travel from a practice to a course, conference or CPD event directly related to your current clinical work
- Travel from a practice to a dental laboratory, supplier or bank for a business purpose
The journeys that are not allowable are:
- Home to your first practice of the day, and your last practice back home, at any of your regular sites
- Travel to a practice you attend on a settled, indefinite schedule, even if it is part-time and not your main practice
- Any private leg, such as a detour to the shops on the way home, even on a day you also did a business journey
The temporary workplace point
A temporary workplace is somewhere you attend to perform a task of limited duration or for a temporary purpose. Travel from home directly to a temporary workplace can be allowable in full, which is why locum-style cover and short fixed-term arrangements behave differently from your settled sites. The key tests are whether the attendance is genuinely time-limited and whether the place becomes, in practice, somewhere you go regularly with no real end in sight. Once attendance at a place is expected to last, or actually lasts, beyond the limits HMRC sets, it stops being temporary and the travel to it becomes commuting again. If you rely on a temporary-workplace argument, write down at the outset why the arrangement is time-limited, because that contemporaneous reasoning is what supports the claim later.
Mileage rates for 2026/27
HMRC publishes approved mileage rates for using your own vehicle for business. For the 2026/27 tax year the rates are:
| Vehicle | First 10,000 business miles | Above 10,000 business miles |
|---|---|---|
| Cars and vans | 55p per mile | 25p per mile |
| Motorcycles | 24p per mile | 24p per mile |
| Bicycles | 20p per mile | 20p per mile |
The car and van figure is significant this year. The 55p rate for the first 10,000 business miles took effect from 6 April 2026 and applies across the whole 2026/27 tax year. It replaced the 45p rate that had stood since 2011, so it is the first increase in well over a decade. The 25p rate above 10,000 miles is unchanged, and motorcycle and bicycle rates are unchanged. Because the relief is given at the rate for the tax year of the journey, anything you are still tidying up for an earlier year is calculated at that earlier year's rate, so always confirm the figure on gov.uk for the year you are actually claiming.
The 10,000-mile threshold resets at the start of each tax year and it applies to you as an individual across all your vehicles combined, not separately per vehicle. Electric and hybrid cars use the same car rate as petrol and diesel. There is no separate, lower rate for electric vehicles, and you cannot add a home or public charging cost on top of the mileage rate, because the approved rate is designed to cover all running costs of the car.
Worked example: an associate across three practices
Consider an associate who splits the week across three sites. She works two days at a practice 12 miles from home, two days at a practice 18 miles from home, and one day at a private clinic 22 miles from home. On the days she does a morning list at one practice and an afternoon list at another, she drives directly between the two, a distance of 15 miles each time.
How the journeys break down:
| Journey | Treatment | Why |
|---|---|---|
| Home to first practice of the day | Not allowable | Ordinary commuting to a regular workplace |
| Last practice back home | Not allowable | Ordinary commuting |
| Practice to practice on a split day (15 miles) | Allowable | Business travel between two workplaces |
| Practice to an evening CPD course | Allowable | Travel for the purposes of the trade |
| Detour to the supermarket on the way home | Not allowable | Private journey |
Suppose she does one split day a week for 45 working weeks, giving 15 miles each way, so 30 business miles a week, which is 1,350 inter-practice business miles a year. Add roughly 150 miles of qualifying CPD and supplier journeys and she has about 1,500 business miles. Comfortably within the first 10,000 miles, that is 1,500 at 55p, which is 825 pounds of allowable expense for the year. As a higher-rate taxpayer that deduction reduces both income tax and Class 4 National Insurance on her profits. The exact saving depends on her marginal position, but the point is that the relief flows entirely from the inter-practice and CPD legs. Not one penny of it comes from the home-to-practice drives, which is precisely why those are the journeys people wrongly try to claim.
Mileage method or actual costs?
There are two ways to claim vehicle running costs, and you use one or the other for a given vehicle, never both.
The mileage method (simplified expenses). You multiply your business miles by the approved rate and claim the total. The rate is meant to cover everything: fuel or charging, insurance, servicing, repairs, road tax and wear. You keep a mileage log but you do not keep fuel or running-cost receipts for the calculation. For most associates this is simpler and gives a sound result, and it is the common choice.
The actual-cost method. You add up the real running costs of the vehicle for the year, then claim the business-use proportion, and you can also claim capital allowances on the vehicle itself. This can produce a larger deduction for an expensive car with high running costs, but it needs full receipts, an accurate business-versus-private mileage split, and more bookkeeping.
Two rules matter when you choose. Once you have used the mileage method for a vehicle, you keep using it for that vehicle until you replace the car. And you cannot use the mileage method on a vehicle for which you have already claimed capital allowances. Because the choice is effectively locked in per vehicle, it is worth running both calculations once when you first start using a car for the business, then sticking with the method that suits it.
The records you must keep
Whichever method you use, a contemporaneous mileage log is the foundation of the claim. For every business journey, record:
- The date of the journey
- The start and end points, including practice names where relevant
- The purpose, for example "practice to practice for afternoon list" or "CPD course on endodontics"
- The distance for that journey
- A running total of business miles for the year, so you can see when you cross 10,000
A notebook, a spreadsheet or a mileage-tracking app are all acceptable, and HMRC accepts digital records. What matters is that the log is built as you go, not reassembled from memory at the year end. If you use the actual-cost method, keep the running-cost receipts and a record of total mileage as well, so you can support the business-use proportion. Keep all of this for at least the period HMRC can open an enquiry into the relevant return.
Three mistakes associates make
Claiming the home-to-practice leg. This is the big one. Working across several practices does not make your first and last drives of the day deductible. They are commuting to and from a regular workplace. Only a genuine temporary workplace changes that.
Mixing private and business miles. A journey only counts to the extent it is for the business. A detour, a school run on the way, or the trip home via the shops is private, even on a day you also drove between practices. Log the business legs precisely and leave the private ones out.
Treating electric cars as a special case. Electric and hybrid cars use the ordinary car rate, and the rate already covers charging. You cannot claim the mileage rate and then add the cost of electricity on top.
How to claim on your Self Assessment
You claim mileage as a business expense in the self-employment pages of your Self Assessment return, within travel costs. Under the mileage method you simply enter the total of your business miles multiplied by the approved rate. Under the actual-cost method you enter the business-use proportion of your running costs and claim capital allowances separately. You do not submit the log with the return, but you must be able to produce it if asked. If your work spans several practices, a company, or a mix of self-employed and employed income, the travel position gets more involved, and a dental-specialist accountant can make sure the claim is both maximised and defensible.
Talk to a dental accountant
Mileage is straightforward in principle, but the line between commuting and business travel, the temporary-workplace test, and the choice of method are all places where associates lose relief or overclaim. At Dental Finance Partners we work with associate dentists across the UK and can review your travel pattern, confirm which journeys qualify, and set up a log that stands up to scrutiny. If you would like a second look at your mileage position, contact our team for an initial discussion.
Mileage checklist for associates
- Treat each regular practice as a workplace, so home-to-first-practice is commuting
- Claim inter-practice, temporary-workplace, CPD and supplier journeys, not your daily commute
- Use 55p per mile for the first 10,000 car or van business miles in 2026/27, then 25p
- Keep a contemporaneous log with date, route, purpose, distance and a running total
- Pick the mileage method or actual costs per vehicle, and do not mix the two
- Review the position whenever your practice schedule or vehicle changes