What did that journey really cost?
Fuel plus wear and tear, worked out properly — so you can split a trip fairly between everyone in the car, or claim it back with a figure you can stand behind.
Tax year 2026/27 · UK
Fuel
Example figures — type over them£11.93Fill the tank before you set off and again when you get back. The second fill is exactly what the trip used — no MPG, no mileage, no guessing.
8.9 litres at £1.34 a litre = £11.93 of fuel.
Wear and tear
£22.47Each one adds up the costs you entered under Build it up from your costs, spread over your yearly mileage. Change a figure there and these move with it.
Where the wear and tear figure comes from
Nobody publishes a wear-and-tear rate on its own, so it has to be worked backwards. HMRC allows 55p a mile tax-free for the first 10,000 business miles. Their separate fuel-only rate for a mid-size petrol car is 17p. The gap — about 38p a mile — is what HMRC reckons everything other than fuel costs you.
That is the ceiling. Build the same figure up from real costs at 8,000 miles a year and you land in the same place, which is a fair sign the number is honest.
Depreciation is the big one and the one people forget. On a mid-range car it is comfortably half the wear cost — more than servicing, tyres and repairs put together.
Charging more than 55p a mile is allowed, but the excess counts as taxable income rather than an expense. The panel flags it when you cross the line. Past 10,000 business miles in a tax year the allowance drops to 25p.
Rates checked September 2026 against HMRC mileage allowance payments and HMRC advisory fuel rates. Both change — the fuel rates every quarter. Nothing here is tax advice.