MilesheetThe economics of always being the one who drives
If you are the designated driver every time, you are subsidising the evening. What that is actually worth, and how to raise it without being awkward.
Every friendship group has one. The person with the estate car, or the one who does not drink, or the one who simply offered once and has been offering ever since.
It is a nice thing to be. It is also, quietly, an expensive one.
The number
Say a 30-mile round trip out and back, twice a month, in a car doing a real 42 mpg with fuel at 145p.
- 60 miles a month is about 6.5 litres, roughly £9.40
- Over a year, about £113 in fuel alone
That is only the consumable. Add the share of tyres, servicing and depreciation those 720 miles used and the true figure is comfortably double. HMRC reckons the whole cost of running a car at 45p a mile, which would put 720 miles at £324.
Nobody is suggesting you invoice your friends at HMRC rates. But it is worth knowing that "just petrol money" is roughly a third of what the lift actually costs.
What it adds up to
Two 30-mile round trips a month, in a 42 mpg car at 145p:
| Fuel only | At HMRC's 45p (full running cost) | |
|---|---|---|
| Per trip | £4.70 | £13.50 |
| Per month | £9.40 | £27.00 |
| Per year | £113 | £324 |
Fuel is roughly a third of what the lift actually costs once tyres, servicing and depreciation are counted. Nobody is suggesting you charge friends the full 45p — but "just petrol money" is not the same as breaking even, and it is worth knowing which one you are doing.
Why nobody offers
Not meanness. It is that the cost is invisible. Passengers see a car that was going there anyway; the driver sees a fuel gauge that moves slightly faster than it used to. Neither has a number, so nothing gets said.
Making it easy to settle
The fix is a figure rather than a conversation. Milesheet records the journey, costs it from your car's actual measured economy rather than a guess, and splits it between whoever was in the car — either everyone including you, or the passengers covering the fuel.
Then send the journey as a PDF. It shows the route, the distance and the cost, and it is much easier to respond to than "do you want to chuck me something for petrol?".
And if any of it was work
Different rules entirely. If you carried colleagues on a genuine business journey, HMRC's passenger payment of 5p a mile per person exists — though for employees it only helps if the employer actually pays it.