A mileage log for your claim, measured by road
Muster keeps a mileage log of the business drives you make in your own vehicle, measures each one by road, and counts the tax year's miles towards HMRC's 10,000-mile step. If you are self-employed, it charges them on your invoice at HMRC's approved rate.
What goes in the log
Every drive is a journey on the Journeys tab: the date, where from, where to, the miles, and whether you have claimed it yet. It is for your own car or van. Flights, trains, taxis, ferries and hire cars belong on Travel instead, because they are not miles you claim at a mileage rate.
There are four ways a drive gets into the log:
- Typed in on the journey form, if you already know the figure.
- At clock-out, where the form asks for the miles driven that day.
- As you go, with the Journey card on Today: tap Start, Add a stop at each call, and End journey. Each tap takes one position. Nothing is recorded between taps, so there is no GPS track of where you went.
- After a travel shift, when Muster asks whether to add that drive to your mileage.
Measured by road, not as the crow flies
A straight line between two places understates every drive you make, so Muster never stores one as mileage. Instead it measures by road on its own map server, and offers the routes it found: the quickest, the fewest miles, and, when it is different, the same road the other way. You pick the one you drove.
- Road figures are rounded to the nearest half mile.
- A figure you typed is never measured over. Yours stands.
- A blank figure is not zero. A journey with no miles yet stays visibly unmeasured, so it cannot quietly pass as a free drive.
- Measuring asks your permission the first time, and can be switched off in Settings.
The steps are in the manual, under Measuring a drive by road and Recording a drive as you go.
Claiming it
At the top of Journeys is one figure: your personal vehicle miles this tax year, from 6 April. It counts every drive, claimed or not, so you can see when you pass 10,000 business miles and the rate steps down. Under it, Before you claim says what is not yet claimed and names any drive with no miles yet. A drive with no figure cannot be claimed until it has one. Each journey has a Claimed for mileage tick, and Mark all claimed up to today is for the day your claim goes in.
| Tax year | First 10,000 business miles | After that |
|---|---|---|
| From 6 April 2026 | 55p a mile | 25p a mile |
| Before 6 April 2026 | 45p a mile | 25p a mile |
Those are HMRC's approved mileage rates for cars and vans, as published in Travel: mileage and fuel rates and allowances on gov.uk, and the rates Muster uses. Each journey takes the rate for the tax year it is dated in.
If you are employed
Muster counts your miles; it does not price them. What a mile is worth is your employer's to say, so no rate is applied and no figure in pounds is shown. There is no separate mileage claim form yet. You claim from the Journeys list, in whatever way your employer asks for. If your employer runs Muster, HR's reports in the admin console show each person's journey miles, and list separately the journeys with no figure. They never show the routes, places or dates.
If you are self-employed
Your drives go on your invoices rather than on a claim. A new invoice ticks the drives on the days that client's hours are billed, and you can tick others. They are charged at your own rate, or at the approved rate for each journey's tax year if you have set none: the same figures as HMRC's simplified expenses for vehicles. A drive with no miles yet cannot be charged. See Invoices for the self-employed.
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