Hi Emma,

The current 308 has a fuel tank of 53 litres, or 11.6 gallons. A 1.6-litre diesel model will do around 76.3mpg, officially, while a 1.2-litre petrol will achieve 57.6mpg. That gives theoretical max cruising ranges of 885 miles (more than 1,400km) for a diesel and 668 miles (1,075km) for the petrol, although in reality you’re more like to get around 1,000km from a diesel’s tank and 700-800km from a petrol.