Average consumption calculator
Average fuel consumption is the number of litres a car uses per hundred kilometres: divide the fuel you filled by the distance covered and multiply by a hundred — that is the real figure, not the manufacturer's test cycle.
- Kilometres per litre
- 13.33km/l
- Miles per gallon (US)
- 31.4mpg
Rates and thresholds
- Formula
- litres × 100 ÷ kilometres
- 5 l/100 km
- 20.0 km/l · 47.0 mpg (US)
- 6 l/100 km
- 16.7 km/l · 39.2 mpg (US)
- 7 l/100 km
- 14.3 km/l · 33.6 mpg (US)
- 8 l/100 km
- 12.5 km/l · 29.4 mpg (US)
- 10 l/100 km
- 10.0 km/l · 23.5 mpg (US)
How do I work out average fuel consumption?
Fill the tank, reset the trip meter, drive as you normally do and fill up again. Divide the second fill by the kilometres covered and multiply by a hundred: 45 litres over 600 kilometres gives 45 × 100 / 600 = 7.5 l/100 km. One tankful is noise; three or four in a row make a dependable average.
Why does the trip computer show less?
A trip computer estimates from injector open time and tends towards optimism, while a fill-to-fill calculation measures the litres you actually paid for. The gap widens on short trips, because a cold engine drinks more. Winter, studded tyres and a roof box all push the figure up noticeably as well.
How do I work out the fuel and cost of a trip?
Multiply the distance by the average consumption and divide by a hundred: 300 kilometres at 7.5 l/100 km takes 300 × 7.5 / 100 = 22.5 litres. For the cost, multiply those litres by the pump price — fuel prices move constantly, so take the number from your last receipt rather than from memory.
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