Fuel Cost Calculator
Fuel is usually the largest variable cost of a road trip and the easiest to estimate wrongly. Enter the distance, the vehicle’s consumption and the pump price to get the real figure, split per person if you are sharing.
Trip & Vehicle
Round trip doubles the distance. Efficiency is usually on the vehicle sticker.
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MPG and L/100km run in opposite directions
Miles per gallon is distance per fuel — higher is better. Litres per 100 km is fuel per distance — lower is better. Because they are reciprocals, MPG is deceptive when comparing improvements. Going from 15 to 20 MPG saves far more fuel over the same distance than going from 40 to 50 MPG, even though the second looks like the bigger jump. L/100km makes the saving obvious.
The sticker figure is optimistic
Official ratings come from standardised test cycles. Real-world consumption is typically 10–20% worse, and considerably worse in city traffic, cold weather, with a roof box, or at sustained high speed. Aerodynamic drag rises with the square of velocity, so cruising at 130 km/h instead of 110 can cost 20% more fuel.
For an accurate figure, fill the tank, reset the trip meter, drive normally for a few hundred kilometres, then refill and divide.
Fuel is not the whole cost of driving
Depreciation, tyres, servicing and insurance typically add as much again per kilometre. National mileage reimbursement rates exist precisely because fuel alone understates the cost of using a vehicle. For a trip-sharing calculation among friends, fuel-only is the normal convention and is what this calculates.