Blog
Splitting fuel and tolls
A road trip is one of the harder things to split, because the money leaves in pieces — several fuel stops, tolls paid at different booths — and the car belongs to one person. Here is each piece separately.
A fuel formula that holds up
Fuel cost = (total distance ÷ fuel economy in km per litre) × price per litre.
For a 400 km round trip in a car doing 14 km/l with fuel at 38 baht/l: (400 ÷ 14) × 38 ≈ 1,086 baht.
Keeping every receipt and totalling the actual spend is more accurate, since it already includes traffic and air conditioning — but only if the tank is filled to full both before leaving and on return, otherwise the two numbers are not comparable.
Should the driver chip in for fuel?
This is what groups fall out over most, and there is no single right answer. Two approaches are common.
Split equally including the driver, on the grounds that everyone made the same journey. This is the simplest to calculate and the easiest to defend.
Or exempt the driver from fuel, treating it as the trade for supplying the car, doing the driving, and carrying the risk, with passengers covering the fuel between them.
Either way, agree on it before setting off rather than once you have arrived.
Wear and tear: count it or not?
On a short trip among friends, wear and tear is usually left out — accounting for it makes the whole thing feel transactional.
On a long trip, a heavily loaded car, or trips frequent enough that the owner is replacing tyres and servicing sooner, adding 1–2 baht per kilometre is reasonable — and should be said openly at the start, not invoiced afterwards.
Tolls, parking, and fines
- Tolls and road charges: split equally among everyone riding in that car.
- Parking: split equally, since everyone benefits from it.
- Traffic fines: the driver's own responsibility, not something to divide.
- Post-trip car wash: up to the group, though splitting it is fair when the mess came from the trip itself.
Two cars need a second round of levelling
When two cars fill up by different amounts, do not let each car settle on its own — whoever happened to ride in the thirstier car ends up subsidising the other group.
Pool the fuel and tolls from every car into one total, divide by the number of people on the trip, and reimburse whoever paid out.
If car one spent 1,800 baht on fuel and tolls and car two spent 1,200, that is 3,000 across 6 people, or 500 each — so driver one gets 1,300 back and driver two gets 700.
Key takeaway
Work fuel out from distance and fuel economy, settle the driver question before you leave, then pool every car into one total and let HarnDuay work out who reimburses whom.
FAQ
How do I work out fuel cost per kilometre?
Divide the price per litre by the car's km-per-litre figure — 38 ÷ 14 ≈ 2.7 baht per kilometre — then multiply by the total distance.
Does the driver pay for fuel as well?
There is no fixed rule: some groups split equally including the driver, others exempt them in exchange for supplying the car and doing the driving. Agree before departure.
How should tolls be divided?
Equally among everyone riding in that car, since all of them benefit from the road equally.
With two cars, should each car settle separately?
No — pool the fuel and tolls from both cars and divide by everyone on the trip, otherwise one carload subsidises the other.