What actually counts as a business mile?

The commute trap, the temporary workplace rule, and the everyday journeys people wrongly leave off their claim.

Liam @ The Milometry Team5 August 2026 · 5 min readLast reviewed 27 September 2026. Figures for tax year 2026-27.

General information, not advice. Written as general information and correct as far as we know on 27 September 2026. Tax rules change, and how they apply depends on your own circumstances. This is not tax, legal or financial advice: check with an accountant, a tax adviser or HMRC before you rely on it.

A lot of underclaimed mileage comes down to uncertainty. People are not sure which drives count, so they leave off the ones they could have claimed and add up the rest badly. Here is the line, in plain terms. These are the rules for employees; the self-employed have similar but not identical tests, which turn on where the business is run from.

"Counts" here means the journey is business travel. Your employer can then pay you for it tax free up to the approved amount (for a car or van in 2026-27, 55p a mile for the first 10,000 business miles in the tax year, then 25p). If they pay less, or nothing, you can claim tax relief on the difference against your own Income Tax (Mileage Allowance Relief). That relief is worth your tax rate on the difference, not the difference itself.

The commute does not count

Travel between your home and your permanent workplace is ordinary commuting, and it is never business travel. It does not matter that you left at six in the morning, or that your employer needed you in on a Sunday.

A permanent workplace is somewhere you attend regularly for your work, other than a temporary workplace. A depot or base you report to, or where your work is handed out, counts as permanent even if you only call in briefly.

Temporary workplaces do count

Travel to a temporary workplace is business travel, and this is where the claims live. A workplace is temporary if you go there to do a task of limited duration, or for a temporary purpose.

The catch is the 24-month rule. If you spend, or it is reasonable to expect you will spend, 40% or more of your working time at a site over a period of more than 24 months, it stops being temporary. Importantly, it stops from the point that expectation becomes reasonable, not when the 24 months elapse. A contract extension can change the answer from the day the expectation changes. A site also stops being temporary if you are expected to work there for all or almost all of the time you are likely to hold the job, which is common with fixed-term and site-by-site contracts.

One more limit: a trip to a temporary workplace does not count if it is, for practical purposes, the same journey as your ordinary commute. HMRC says it will not normally argue this where the trip is 10 miles or more each way longer.

Journeys that usually count

Driving to a client, a customer, a supplier or a site
Travelling between two workplaces on the same day
Going from home directly to a temporary site, if you are not going via the office and the route is not substantially your usual commute
Driving to a conference, training course or trade show your work requires
A trip to the bank, the post office or the wholesaler for the business, if you are self-employed

Journeys that usually do not

Home to your permanent workplace, whatever the time or day
A detour for something personal, for the personal part of the distance
Taking a colleague home after work, unless it is part of a business journey
Driving somewhere purely social, even with people from work

The awkward middle: home as a workplace

Journeys from home to a client or a temporary site are business travel whether or not you work from home. What home working does not change is the drive to your employer's office: that is still commuting. It only becomes business travel in the rare case where working at home is a requirement of the job (not a choice) and where you live is itself dictated by the job, and then only on days when home is a workplace. Working from home three days a week by preference does not turn your Thursday commute into a business mile.

Why the recording matters more than the rules

Two people can drive identical routes and only one of them can claim, because only one of them can say what the journey was for. A date, a start, an end, a distance and a reason is what turns a drive into a claim. Reconstructing that from memory in April is where accuracy goes to die.

That is why Milometry asks one question and only one: business or personal. It already knows the date, the route, the distance and how long you were stopped. You just tell it what the drive was for, ideally on the same day, when you can still remember.

The quick reference

Journey	Claimable?	Why
Home → permanent workplace	No	Ordinary commuting
Home → temporary workplace	Yes	Unless substantially your usual commute
Home → client, direct	Yes	Unless substantially your usual commute
Office → client → office	Yes	Travel in the performance of duties
Office → client → home	Usually yes	Unless you detour somewhere personal
Home → office → client	Mixed	First leg commuting, second leg business
Permanent workplace → second permanent workplace, same employer	Yes	Travel between workplaces
Home → workplace of a second, unconnected employer	No	Commuting for that employment
Home → workplace of a second employer in the same group	No	Commuting for that employment
Workplace of one group company → workplace of another	Often yes	Travel between group employments
Detour to the shops on the way back from a client	Partly	The business element only
Driving to a training course required by the job	Usually yes	If the course venue is a temporary workplace

The three tests, in order

Work through these and most journeys resolve:

Is this a workplace you attend, or somewhere you are going for work? A client visit is straightforwardly business travel.
If it is a workplace, is it permanent or temporary? Apply the 24-month rule, remembering it turns on what you expect, not what has happened so far.
If it is permanent, is the journey between two workplaces rather than from home? Workplace to workplace for the same job (or between companies in the same group) is business travel; home to workplace is not.

What a defensible record looks like

Field	Example	Why it matters
Date	14 August 2026	Ties to your calendar and invoices
From	Home	Establishes the journey type
To	Harrogate, Acme Ltd	Names the workplace, not just a town
Purpose	Site survey	The business character, in a few words
Distance	18.4 mi	Not a round number, because real drives are not round
Vehicle	Van (AB26 CDE)	Keeps multi-vehicle totals apart

The purpose column is the one people leave out and the one that turns a list of distances into a record. "Site survey" takes three seconds and answers the question HMRC would actually ask.