True MPG: which cars beat their official figures – and which are farthest away?
Our True MPG tests show what fuel economy you can really expect from a car, with some models beating their official figures but others falling more than 26% short...
New cars 6.3% less efficient than official figures
New petrol, diesel and hybrid cars are on average 6.3% less efficient in real-world conditions than the official WLTP figures suggest, What Car? has found.
We put 96 popular models through our independent True MPG test, with the worst performers 26% down on their official figures, and the best almost 19% up.
WLTP is, however, a lot more accurate than the old NEDC system, which it replaced in September 2018; a previous sample of 159 vehicles type approved to NEDC standards showed an average discrepancy of 20.2% between True MPG and the official results, with the worst performers as much as 40% less efficient than advertised.
To ensure accuracy and repeatability, our True MPG tests are conducted in strictly controlled laboratory conditions, but they are based on a real route that takes in town, rural and motorway driving.
As a result, they reflect what's achievable if you’re driving gently and sticking to speed limits but aren’t resorting to any unrealistically slow acceleration or special 'hypermiling' techniques.
Which of the latest models were farthest away from their official figures, though, and which over-achieved? Let's take a look, starting with the 10 biggest under-performers...
10. Hyundai i20 1.0 T-GDi SE Connect
Official WLTP average 55.4mpg | True MPG 47.8mpg | Shortfall -13.7%
The i20's 99bhp mild hybrid petrol engine is pleasantly peppy and doesn't feel out of breath on faster roads, it's just a shame that you'll spend more money on fuel than the official figures would have you believe. Elsewhere, this small Hyundai offers roomy rear seats and holds onto its value well.
=8. BMW 118i M Sport
Official WLTP average 42.8mpg | True MPG 36.3mpg | Shortfall -15.2%
The latest BMW 1 Series family hatchback has impressed us with its superb interior build quality, class-leading infotainment system and sporty handling, and while the 1.5-litre petrol engine which powers this version is powerful enough for most people, it's also more than 15% adrift of its official fuel economy figure.
=8. Ford Focus 2.3 Ecoboost ST
Official WLTP average 34.9mpg | True MPG 29.6mpg | Shortfall -15.2%
The regular Ford Focus already stands out as the best driver’s car in the family car class, but this ST version adds hot hatchback thrills into the mix too. We like its great driving position and the fact that it comes with a lot of kit, but you'll be spending a considerable amount of time at the petrol pumps, with real-world fuel economy of just under 30mpg.
7. Audi Q2 1.5 35 TFSI S Line
Official WLTP average 45.6mpg | True MPG 38.5mpg | Shortfall -15.6%
The Q2 is a good choice if you want a small SUV with a premium badge on its bonnet, and while the badge means it's more expensive than most rivals, the Q2 fights back with a classy interior, tidy handling and slow depreciation. This 1.5-litre petrol engine is our favourite option in the range, with noticably more punch than the entry-level 1.0-litre engine.
6. BMW 3 Series Touring M340i M Sport
Official WLTP average 33.2mpg | True MPG 28.0mpg | Shortfall -15.7%
This is the hottest 3 Series Touring currently available, delivering effortless performance and entertaining handling, plus it's a practical choice thanks to its big boot. Just don't expect it to be a frugal one; we managed a True MPG of 28.0, and you'll see a lot less than that if you drive the car the way it wants to be driven.
5. Audi A3 Saloon 1.5 35 TFSI 150 S Line
Official WLTP average 48.7mpg | True MPG 40.9mpg | Shortfall -16.0%
The second Audi to feature among our bottom 10 performers is the A3 Saloon, and it's even further adrift of its official fuel economy than the Q2 small SUV we saw earlier. Despite this, however, we're still fans of this executive saloon, which offers a good balance of ride comfort and agile handling and comes with lots of kit.
4. Renault Clio 1.6 Petrol Hybrid 140 Iconic E-Tech
Official WLTP average 64.2mpg | True MPG 51.6mpg | Shortfall -19.6%
This version of the Clio is pleasantly punchy, but because it's a hybrid it can also run for short distances on electric power alone. We like its class-leading safety kit and practical boot, but rivals have better infotainment systems.
3. Ford Fiesta 1.0 155 ST-Line X
Official WLTP average 53.3mpg | True MPG 42.7mpg | Shortfall -19.9%
The Fiesta is great to drive, with engaging handling and a peppy 1.0-litre petrol engine under the bonnet. You'll want to go for an ST-Line car, too, since this gets you stiffer suspension which helps the car to stay more upright and composed through corners. Rivals are more practical and represent better value, and you'll spend less on fuel than you will with this Fiesta.
2. Suzuki Swace 1.8 Hybrid SZ-T
Official WLTP average 64.2mpg | True MPG 50.3mpg | Shortfall -21.6%
The Swace is essentially a rebadged version of the Toyota Corolla, and shares that car's hybrid engine. Despite being able to run on electric power for short distances, however, it's still far adrift of the official government fuel economy figure. At least it impresses with a comfortable ride and lots of standard kit.
1. BMW 420d M Sport Pro Edition
Official WLTP average 57.6mpg | True MPG 42.4mpg | Shortfall -26.4%
Our reigning Coupe of the Year might be more fun to drive than its rivals and surprisingly practical, but there's no getting around the fact that you'll spend significantly longer at the pumps than the official figures would have you believe, with this version being more than a quarter adrift of its official figures. At least this diesel-powered version provides plenty of low-down pull and is great for motorway trips.
Next, the 10 biggest over-achievers...
10. Kia Sorento 2.2 CRDi diesel 3
Official WLTP average 42.2mpg | True MPG 42.3mpg | Improvement +0.3%
It's the hybrid version of the Kia Sorento which we named as our Large SUV of the Year back in January, but this diesel-powered version is a good choice for those who do lots of miles. Like other Sorento models, it's massive inside and well equipped, and will also be surprisingly efficient on fuel.
9. Lexus LC500 Cabriolet 5.0 V8 Sport Plus Pack
Official WLTP average 24.1mpg | True MPG 24.2mpg | Improvement +0.5%
The LC will certainly turn heads as you drive along, and passers by will definitely hear you coming thanks to the amazing noise from its V8 engine. Such a car will never be cheap to run, but we're pleased to see that the LC is at least slightly more efficient than the official figures suggest.
8. Toyota GR Yaris 1.6 Petrol (Non-Circuit Pack)
Official WLTP average 34.3mpg | True MPG 35.9mpg | Improvement +4.5%
You won't be surprised to hear that this go-faster version of the Yaris is great to drive and has no trouble putting a smile on your face – after all, it's our reigning Hot Hatch of the Year. It's also more efficient than you might expect, so you might also find that it's kind to your wallet as well as your heart.
7. Suzuki Ignis K12D 1.2 Dualjet Hybrid SZ-T
Official WLTP average 55.7mpg | True MPG 59.9mpg | Improvement +7.5%
This version of the Ignis averaged almost 60mpg on our tests, and that's hugely impressive for a small SUV. Don't let the Ignis' size fool you, though, because it's also remarkably spacious inside. We also like the Ignis' long list of standard kit, which on SZ-T trim includes 16in alloy wheels, a rear-view camera and a touchscreen infotainment system.
6. Skoda Karoq 1.5 TSI SE-L
Official WLTP average 40.5mpg | True MPG 44.2mpg | Improvement +9.1%
The Karoq is basically the Seat Ateca's less sporty sister, but its more rounded nature isn't necessarily a bad thing. The Karoq offers a more polished ride and superior seating flexibility, for starters. And while the Ateca is officially the more efficient option, in reality it's the Karoq that ekes more miles per gallon out of the turbocharged 1.5-litre petrol engine that both cars use.
5. Honda Civic Type R GT
Official WLTP average 33.2mpg | True MPG 36.3mpg | Improvement +9.2%
What's better than a car that's good to drive and suprisingly practical? Well, that would be one which also turns out to be significantly less expensive to run than you might expect. This Type R is wonderful fun, but can also be used every day without ruining your spine. It is noisy, though, and there are cheaper hot hatchbacks.
4. Dacia Duster 1.3 TCe 130 Comfort
Official WLTP average 39.8mpg | True MPG 43.8mpg | Improvement +10.1%
The Duster already represents great value for money, even before you factor in that it beats it's official fuel economy figure by more than 10% in real-world conditions, which means you can spend less time at the pumps and more time enjoying it's spacious and practical interior.
3. Volkswagen Up 1.0 S/S 60PS R-Line
Official WLTP average 50.7mpg | True MPG 56.0mpg | Improvement +10.5%
Small and nimble, the Up is a good choice if you live in the city, being fun to drive and having a relatively classy interior. It's a bonus that this 1.0-litre petrol-engined version is also significantly more frugal than the official figures would have you believe.
2. Honda CR-V 2.0 i-MMD Hybrid SR
Official WLTP average 42.2mpg | True MPG 47.4mpg | Improvement +12.3%
Although we've seen two hybrids rank among the car which fall well short of their official test results, the Honda CR-V shows that not all hybrids should be painted with the same brush, because this practical and refined SUV beats its official mpg by more than 12%. The CR-V has a poor infotainment system, though, and its CVT automatic gearbox has a habit of sending the engine's revs soaring.
1. Ford Ranger 2.0 Diesel Thunder
Official WLTP average 30.7mpg | True MPG 36.5mpg | Improvement +18.9%
No, your eyes aren't deceiving you, the car which beats its official test result by the biggest margin is indeed a diesel-powered pick-up truck. Aside from its fuel economy, though, there's plenty else to like about our reigning Pick-Up Truck of the Year, including its comfortable ride, gutsy engine and competitive pricing.
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