Most people assume business mileage is straightforward.
If you drive for work, you claim it. Simple.
Except HMRC’s actual rules are slightly more nuanced than that.
And this is where a lot of taxpayers accidentally:
- • overclaim
- • underclaim
- • or avoid claiming entirely because they are worried about getting it wrong
Understanding what counts as legitimate business mileage is becoming increasingly important, especially with the mileage allowance rising to 55p per mile.
The Basic Rule
In general, business mileage applies when you use your own vehicle for qualifying work-related travel.
This can include:
- • driving to client sites
- • travelling between workplaces
- • supplier visits
- • temporary work locations
The key principle is that the journey must be wholly and exclusively for business purposes.
What Usually Counts as Business Mileage
Common qualifying journeys include:
Client visits
Driving to see customers or clients generally qualifies.
Temporary workplaces
Travelling to a temporary site or short-term location usually counts.
Multiple work locations
If your work involves moving between sites during the day, those journeys are typically allowable.
Supplier or business purchases
Collecting tools, stock or materials for business use usually qualifies.
What Usually Does NOT Count
This is where people get caught out.
Ordinary commuting
Driving from home to your normal permanent workplace is usually not allowable. HMRC treats this as personal commuting rather than business travel.
Personal errands
Stopping at the supermarket on the way home from work does not suddenly turn the whole journey into business mileage.
Mixed-purpose trips
If a journey combines personal and business activity, only the genuine business element may qualify.
Why Permanent vs Temporary Workplace Matters
This is one of HMRC’s biggest distinctions.
A temporary workplace generally means somewhere attended:
- • for a limited duration
- • or temporary purpose
Whereas a permanent workplace is somewhere attended regularly as part of normal work.
For contractors and CIS workers especially, this distinction can become very important.
Why Good Records Matter
The biggest protection is good documentation.
A proper mileage log should ideally include:
- • date
- • destination
- • purpose of trip
- • miles travelled
This matters both for accurate claims and as supporting evidence if HMRC ever asks questions.
Official guidance: gov.uk/tax-relief-for-employees/vehicles-you-use-for-work.
The Real Problem: Most People Guess
In reality, many people:
- • estimate mileage
- • round figures up or down
- • forget journeys
- • keep incomplete logs
This often leads to either:
- • underclaiming legitimate expenses
- • or creating weak evidence for claims made
Neither outcome is ideal.
Summary
Business mileage rules are simpler once the core principle is understood: the journey must genuinely relate to business activity rather than ordinary commuting or personal travel.
Common qualifying journeys include:
- • client visits
- • temporary work locations
- • supplier trips
- • travel between work sites
Meanwhile ordinary commuting usually does not qualify.
With mileage allowances now increasing to 55p per mile, understanding the rules properly could make a noticeable difference to how much legitimate tax relief workers and sole traders are able to claim.