True MPG: how close to reality are official fuel economy figures?

What Car?'s True MPG test reveals official fuel economy figures are closer to reality than ever… but still an average of 4.9% worse than claimed...

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What Car? team
15 March 2019

Citroën C4 Cactus

Citroën C4 Cactus Puretech 110

Engine 3cyl, turbo, petrol Gearbox Manual

Official economy 49.8mpg True MPG 44.2mpg Difference -11.2%

Read our Citroën C4 Cactus review or see what discounts are available


BMW 3 Series 320d

BMW 3 Series front quarter driving

Engine 4cyl, diesel Gearbox Automatic

Official economy 54.3mpg True MPG 47.2mpg Difference -13.1%

Read our BMW 3 Series review or see what discounts are available


BMX X2 xDrive20d

New BMW X2 & Jaguar E-Pace vs Volvo XC40

Engine 4cyl, diesel Gearbox Automatic

Official economy 48.7mpg True MPG 39.6mpg Difference -18.7%

Read our BMW X2 review or see what discounts are available


Ford Fiesta 1.0 Ecoboost 140

Ford Fiesta

Engine 3cyl, turbo, petrol Gearbox Manual

Official economy 48.7mpg True MPG 38.3mpg Difference -21.4%

Read our Ford Fiesta review or see what discounts are available


Volvo V60 D4

Volvo V60

Engine 4cyl, diesel Gearbox Automatic

Official economy 48.7mpg True MPG 38.3mpg Difference -21.4%