Business Mileage vs Commuting: Where HMRC Draws the Line

Published 28th January 2026

This is the number one thing people get wrong with mileage claims. "But I drove to work!" isn't a mileage claim. HMRC draws a very specific line between business travel and commuting, and if you get it wrong, you're looking at an incorrect tax return, a bill, and possibly penalties. Let me clear it up so you can claim properly and sleep at night.

The Basic Rule: Ordinary Commuting Is Not Business Mileage

Ordinary commuting = home to your regular workplace. That's it. Doesn't matter if it's 50 miles each way or costs you £200 a month in petrol. HMRC says that's your problem. Driving, train, bus, bicycle -- makes no difference. Commuting is personal. End of.

Your "permanent workplace" is where you regularly go to do your job. For most people, that's the office, the shop floor, the depot, or the factory. If you go there regularly and do a significant chunk of your work there, it's permanent.

The key question: Is the journey to a permanent workplace, or is it to a temporary workplace? This single distinction determines whether you can claim mileage.

What Is a Temporary Workplace?

A temporary workplace is somewhere you go for a limited time to do a specific task. HMRC says it's temporary if you attend (or expect to attend) for less than 24 months, and it isn't your usual base. Travel to temporary workplaces? That's business mileage. You can claim it.

Think things like:

A client's premises where you are working on a specific project
A conference or training venue
A branch office you visit occasionally but is not your main base
A construction site where you are working for a defined period
A temporary office while your regular workplace is being refurbished

The 24-Month Rule

This is the rule that trips people up. Once you've been going to a site for more than 24 months -- or you expect to -- it stops being temporary. Spend more than 40% of your time there over a period exceeding 24 months? Same thing. It becomes permanent, and your travel becomes commuting. No more mileage claim.

Example 1: Sarah is a consultant who is assigned to a client's office for an 18-month project. Because the assignment is less than 24 months, the client's office is a temporary workplace. Sarah can claim mileage for all journeys from her home to the client's office.

Example 2: The same project is extended to 30 months. From the point Sarah knows the project will exceed 24 months, the client's office becomes a permanent workplace. She can no longer claim mileage for that journey.

Home Workers and Business Mileage

Hybrid working has made this whole area more confusing. The crucial question: is your home your permanent workplace, or is the office?

Home as your permanent workplace

If your contract says your workplace is your home, and you don't have a regular desk at the office, then your home is your permanent workplace. Trips to the office become business travel to a temporary workplace -- and you can claim them. The condition: you need to attend the office less than 40% of the time over a period under 24 months.

Home as a convenience

This is where most hybrid workers get it wrong. If you've got a permanent desk at the office and just choose to work from home some days, the office is still your permanent workplace. Driving there on a Tuesday? That's commuting. Doesn't matter that you worked from home Monday, Wednesday, and Friday. The office hasn't changed just because you're not there every day.

The mistake I see constantly: "I work from home three days a week, so my two office days must be business mileage." Nope. If that office is still your permanent workplace, those journeys are commuting. Working from home doesn't magically change the status of the office.

Multiple Workplaces

Work at more than one site? This is where it gets a bit nuanced:

Multiple permanent workplaces: If you regularly work at two offices (for example, Monday to Wednesday at one and Thursday to Friday at another), both could be considered permanent workplaces. Travel between them during the working day is business mileage, but travel from home to either one is commuting.
One permanent, others temporary: If you have one main office and occasionally visit other sites, the other sites are likely temporary workplaces. Travel to those sites is business mileage.
Area-based workers: Workers who travel to multiple locations as part of their job (such as district nurses, sales representatives, or maintenance engineers) generally have no permanent workplace. Their travel from home to the first job of the day, and from the last job back home, may be claimable depending on the specific circumstances.

Travel During the Working Day

Good news here: any travel between business locations during the working day is always business mileage. Office to client meeting and back? Claimable. Three client visits in one day? All claimable. This is the straightforward bit of the rules.

Common Mistakes to Avoid

Claiming the commute from home to the office: This is the most basic error. Unless your home is genuinely your permanent workplace, this journey is commuting.
Ignoring the 24-month rule: If you have been at a temporary site for a long time, check whether the 24-month threshold has been breached or is likely to be breached.
Not adjusting for hybrid working: Working from home part of the week does not automatically make your office a temporary workplace.
Claiming personal detours: If you make a personal stop during a business journey (such as dropping children at school), you must exclude the additional miles that are not part of the direct business route.
Forgetting to deduct commuting miles: If you travel from home to a temporary workplace but the route passes through your permanent workplace, you may need to deduct the commuting portion of the journey.

What If You Get It Wrong?

If HMRC catches you claiming commuting as business mileage, you'll repay the tax relief plus interest. Careless errors can attract penalties of up to 30%. Deliberate ones? Much worse. It's really not worth the risk.

Best protection: keep clear records of every journey with the business purpose noted. If you're not sure whether a trip qualifies, don't claim it. The few quid you'd save isn't worth the stress of an investigation.

Use our mileage claim calculator to work out the value of your legitimate business mileage claims.