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 April 2019

Polestar 1 emissions testing

What Car?’s True MPG testing has revealed that new government fuel economy tests introduced late last year are providing more accurate results than ever before – with some cars even beating their official figures in the real world.

However, the average gap between the official claimed fuel economy and what we've found to be realistic in the real world remains close to 5%.

That's far better than the 23.5% average shortfall for cars tested before the new regulations came into effect, with the worst result ever recorded by What Car? being a 41% difference. But it highlights the fact that car buyers should remain wary of taking official figures for granted – especially given that some models are still falling more than 20% short.

In a 15-car sample that ranged from small hatchbacks to SUVs, petrols to diesels and automatic to manual gearboxes, the economy figures published in sales brochures were, on average, 4.9%, or 2.6mpg, higher than our testers achieved.

Below we take a look at all of the results, from the best to the worst.

Mazda MX-5 2.0

Mazda MX-5 front

Engine 4cyl, petrol Gearbox manual

Official economy 40.9mpg True MPG 45.1mpg Difference +10.3%

Read our Mazda MX-5 review or see what discounts are available


Skoda Karoq 1.5 TSI 150

Skoda Karoq 2019 front cornering shot

Engine 3cyl, turbo, petrol Gearbox Manual

Official economy 40.9mpg True MPG 44.2mpg Difference +8.1%

Read our Skoda Karoq review or see what discounts are available


Skoda Superb Estate 2.0 TDI 150

New Volvo V60 vs Audi A4 Avant vs Skoda Superb Estate

Engine 4cyl, diesel Gearbox Automatic

Official economy 51.4mpg True MPG 54.8mpg Difference +6.6%

Read our Skoda Superb Estate review or see what discounts are available


Seat Ateca 1.5 TSI 150

Used Seat Ateca 16-present

Engine 4cyl, turbo, petrol Gearbox Manual

Official economy 42.2mpg True MPG 44.5mpg Difference +5.5%

Read our Seat Ateca review or see what discounts are available


Nissan Qashqai 1.3 DiG-T 140

Nissan Qashqai

Engine 3cyl, turbo, petrol Gearbox Manual

Official economy 39.8mpg True MPG 41.3mpg Difference +3.8%

Read our Nissan Qashqai review or see what discounts are available


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