Road trip cost calculator
A 1,200 km drive at 6.5 l/100 km burns 78 litres, which is two refuels on a 45 litre usable tank. Each stop is realistically twenty minutes once you have queued, paid and used the facilities, and it is where the coffee and sandwich money goes. The fuel figure below is exact; the trip budget is that plus about the same again in stops if there are four of you.
Trip fuel is distance times consumption times price. A 1,200 km drive at 6.5 litres per 100 km uses 78 litres; at 1.85 per litre that is 144, or 36 each between four people, and it needs two refuel stops on a 45 litre usable tank.
How to budget a road trip
Real consumption on a long motorway run is usually a little worse than the official combined figure, not better, because sustained high speed costs more than the mixed cycle the test uses. Add a roof box and it gets markedly worse — 10 to 20% is typical, since drag rises with the square of speed. Loading four people and their luggage adds a few per cent more. If you are budgeting, take your normal consumption figure and add ten per cent before entering it here.
Questions
Distance divided by economy times price. Use your real-world consumption and add about 10% for motorway speed and a loaded car.