HMRC mileage log requirements: what your log must show

HMRC's mileage log requirements come down to one test: could a stranger tell, from the log alone, where you went and why it was for work? For an employee claiming tax relief on a P87, GOV.UK spells it out. You send a copy of a mileage log for each employment, giving the reason for every journey and the postcodes where it started and ended. Add the date and the business miles, which you need to work out the claim anyway, and that is the core of every mileage log HMRC will accept.

Who is asking changes the details. Employers, sole traders and VAT-registered businesses each need a little more, so here is the full picture, plus an example log you can copy.

What HMRC requires, by who you are

What a mileage log must include

Put the requirements together and a sound log has one row per journey with these columns:

• Date of the journey.
• Start postcode and end postcode, not just "home" and "site".
• Reason: who you saw or what you did.
• Business miles for the journey.
• Vehicle: car or van, motorcycle or bicycle, because each kind has its own rate and is added up separately.
• What your employer paid, if anything, so the difference can be worked out.

Here is what that looks like in practice:

Two things are missing on purpose: the drive home from the trade counter, which was private, and anything that was a commute.

Writing a reason HMRC will accept

The reason column is where most logs fail. "Meeting", "client", "site visit" and "business" all tell HMRC that you were somewhere, not why. Name the person, the job or the address: "Boiler service, 22 Elm Road" or "Pitch to Northgate Dental". If you visit the same client every week, the same reason every week is fine, as long as it is true.

Keep the log as you go. A log typed up in March from memory and bank statements tends to look exactly like a log typed up in March, and if HMRC asks, you want records written at the time, with a diary or job sheet behind them.

Employees claiming tax relief on a P87

If your employer pays you less than the approved mileage rate, or nothing at all, you can claim tax relief on the difference. From 6 April 2026 that rate is 55p a mile for the first 10,000 business miles in a car or van, then 25p; motorcycles are 24p and bicycles 20p. The 2026/27 mileage rates guide has the full table.

Since 14 October 2024, HMRC has asked for evidence before it processes these claims, and for mileage the evidence is the log. Claims of up to £2,500 can go through PAYE, online or on the paper P87 form; if you fill in a Self Assessment return, the claim goes on the return instead. You can claim for the current tax year and the four before it, so a log from 2022/23 can still earn its keep.

Employers paying mileage allowance

An employer paying Mileage Allowance Payments within the approved amount reports nothing to HMRC. HMRC's own manual (EIM31390) is clear that this is not the same as keeping nothing: the employer "will still need to keep records of the payments made and the business journeys to which they relate". In practice, that means keeping each employee's log with the claim it was paid on.

Anything paid above the approved amount goes on the employee's P11D and is taxed as pay. Passenger payments of up to 5p a mile are tax-free on top.

Self-employed: simplified expenses or actual costs

Sole traders, and partnerships with no company partners, can claim vehicle costs at the flat rate (the same 55p and 25p for cars and vans, 24p for motorcycles). GOV.UK's first step is to keep records of your business miles for each vehicle, so the log is the claim. Once you use the flat rate for a vehicle, you stay on it for as long as that vehicle is in the business.

If you claim actual costs instead, such as fuel, insurance and repairs, you can only claim for business driving, not "non-business driving or travel costs". The log is what shows the business share: business miles against total miles for the year.

Either way, keep your records for at least five years after the 31 January filing deadline for the tax year. How long to keep receipts covers the other rules, and allowable expenses for sole traders covers what else you can claim.

Company cars

In a company car, the approved mileage rates do not apply. You can claim relief on what you spent on fuel or electricity for business trips, less anything your employer repaid, and GOV.UK asks you to keep records showing the actual cost of the fuel.

The log matters the other way round too. There is no fuel benefit charge for private fuel if the employer correctly records all private mileage and the employee repays it at the right rate. Our guide to advisory fuel rates for company cars has the rates and the all-or-nothing catch.

VAT on fuel: the extra columns

VAT Notice 700/64 asks more of VAT-registered businesses. If you pay employees a mileage allowance and reclaim VAT on its fuel element, your records for each employee must show the mileage travelled, whether the journey was business or private, the vehicle's cylinder capacity, the rate of mileage allowance and the input tax claimed. You also need fuel VAT invoices that cover the business fuel, and none dated after the period you are claiming for.

If the business pays for both business and private fuel and you do not use the fuel scale charge, you must keep detailed mileage records to split one from the other. The same goes for electric cars: HMRC says to work out the business share of charging costs by keeping mileage records. For the receipts side, see what counts as a valid VAT receipt.

Frequently asked questions

Do I need a mileage log for tax purposes?

If you claim mileage in any form, yes. An employee's P87 claim is not processed without one, an employer needs records to pay mileage tax-free, and a sole trader works out the flat-rate claim from business miles. If you never claim a mile, you do not need one.

How detailed does a mileage log have to be?

One row per journey, with the date, start and end postcodes, the reason and the miles. GOV.UK names the reason and the two postcodes for P87 claims, and VAT records need more. If one trip has several stops, log each leg with its own reason.

How do you prove mileage to HMRC?

With a log kept at the time, backed by whatever shows the journey happened: job sheets, invoices, appointment emails or diary entries. For company cars, add the fuel receipts.

Is there an official HMRC mileage log template?

The GOV.UK guidance quoted here sets out what a log must contain, not a layout. Paper, a spreadsheet or an app all work, as long as every journey has the details above and you can produce a copy when asked.

Do I need odometer readings?

The P87 evidence list does not mention them. If you claim actual costs or split fuel for VAT, though, you need your total miles as well as business miles, and readings at the start and end of the year are the simplest way to get them.

Where ClaimSnappy fits

We built ClaimSnappy's mileage around that list. Each journey is saved with its date, reason, miles and vehicle, and its start and end postcodes. You add trips on the website by typing the start, any stops and the finish, tapping them on the map, or typing the miles. A trip cannot be saved without a reason, and a vague one such as "Meeting" is flagged with a suggestion. If you have set a home pin, "Home" in the log gets your postcode.

Before a claim goes, the checks flag miles well over the route, the same journey logged twice, and trips logged more than 90 days after the event, so you can fix them while you still remember the day. A journey missing a postcode is flagged before it goes on a P87.

You build each claim and send it yourself, and on a team desk it can go to a manager for approval first. Every claim downloads as a PDF and CSV, and the Reports page prepares a P87, with the mileage log, for what your employer did not pay back. Your accountant sees it all in the free accountant portal, where they can also export year-end mileage logs.

Try it on a 30-day trial with no card; after that, Solo is £5 a month. See how it works if you claim for yourself or run a team, or compare plans.

ClaimSnappy keeps the records. Whether a journey qualifies is for you, your employer and HMRC to settle, and if you are unsure, an accountant is cheaper than a rejected claim.