Real MPG: the least economical new cars you can buy
What Car?'s Real MPG tests show what fuel economy you can really expect from a car. Here are the least efficient models you can currently buy in the UK...
If fuel economy is a priority for you, then you’ll want to avoid a car that’ll have you stopping to fill up often. However, it’s not always easy to tell what your car will truly be able to achieve, since the official fuel economy figures you see in manufacturers’ sales brochures can be misleading.
That’s why we conduct our own Real MPG tests, which simulate a route combining urban, motorway and rural driving, and avoids unrealistic ‘hypermiling’ techniques to produce a more authentic result of what you can expect from your car.
Here, we’ve listed the ten cars currently on sale that performed worst in our tests. So, if your next car needs to be cheap to run, then it’s worth avoiding these and taking a look at our rundown of the most economical cars you can buy.
Still, that’s not to say these cars aren’t impressive. In fact, the Audi S8 that tops this list is the least economical car we’ve tested, but its savage pace and refined drive earned it five stars in our review.
How we test for a car's Real MPG
Our Real MPG tests are conducted under laboratory conditions using a rolling road, where each car undertakes a real-world-inspired route that combines urban, motorway and rural driving.
Each car is checked to ensure that it meets all the manufacturer’s recommendations, including having all its tyres correctly inflated.
Climate control is set to 21 degrees, or if the car has manual air conditioning, the temperature dial is set to the midway point and the fan speed to its lowest setting. All other electrical equipment is switched off.
We calculate the Real MPG results using the average data from an exhaust connection, which measures the car’s emissions at every second.
Read more: How we test a car's Real MPG
Our pick: S8 Quattro Vorsprung 4dr Tiptronic
Strengths
- Savage straight-line pace
- Comfortable and incredibly refined
- Plush interior
Weaknesses
- Not the most agile performance car
- Muted engine note won’t appeal to all
- Fiddly infotainment system
WLTP MPG 24.6mpg | Real MPG Average 21.7mpg | Town 13.5mpg | Motorway 23.8mpg | Rural 27.6mpg
This range topping version of the Audi A8 is eye-wateringly expensive to begin with, so if you can afford to put one on your driveway, the chances are that low running costs aren’t a priority. Indeed, the S8 is the least economical model to have ever gone through our tests, scoring a real-world average of just 21.7mpg.
That being said, there’s no doubt that the S8 is otherwise a great car in our eyes. Its thundering 563bhp 4.0-litre V8 petrol engine delivers staggering performance with a pleasant-sounding growl to go alongside it. It’s certainly not short on thrills – despite weighing a hefty 2.3 tonnes, the S8 can race from 0-62mph in just 3.8sec.
A smooth ride and top-notch interior give the S8 that real luxury car feel, and you’ll find that there’s plenty of room inside for all your passengers and their luggage. However, it’s not quite as agile as some of its high-performance rivals, such as the Mercedes E63 AMG, and the touchscreen infotainment system can be distracting.
Read our full Audi S8 review
Strengths
- Big cargo bay with a high payload capacity
- Space for four six-footers in Double Cab versions
- Good to drive for a pick-up
Weaknesses
- Not the cheapest pick-up
- Warranty could be better
WLTP MPG 20.5mpg | Real MPG Average 24.0mpg | Town 16.0mpg | Motorway 24.1mpg | Rural 32.2mpg
Despite being one of the least economical cars we’ve ever tested, the Ford Ranger Raptor actually managed to beat its official figure by 3.5mpg in our real-world testing.
The Raptor comes equipped with a 288bhp 3.0-litre V6 engine, which is designed to deliver sporty performance, while still benefitting from the practicality of the regular Ford Ranger pick-up. And it certainly delivers, with surprisingly solid handling for a car of its size.
Naturally, the Raptor feels right at home off road, thanks to a strong arsenal of chunky tyres, hardcore 4x4 system and sophisticated traction control software. However, you might find that the diesel version better suits your needs if you’re looking for a cheaper, more efficient car.
Read our full Ford Ranger review
Strengths
- Cheap by all-wheel-drive sports SUV standards
- Just as practical as a regular Seat Ateca
- Very well equipped with a user-friendly dash
Weaknesses
- Interior starting to look dated
- So-so interior quality
- Engine could sound fruitier
WLTP MPG 31.4mpg | Real MPG Average 28.5mpg | Town 23.1mpg | Motorway 26.9mpg | Rural 35.0mpg
This particular version of the Cupra Ateca sports SUV is the range-topper, complete with 296bhp, four-wheel drive and low, stiff suspension that will have you sailing through fast corners at serious speed.
All this sporty performance comes at a price, though, and the Ateca will have you stopping to fill up much more than the regular petrol or diesel equivalent. Despite that, it’s largely good to drive, with a smoother ride than than rival Ford Puma ST and a pleasantly quiet engine at speed.
The Ateca’s interior isn’t quite as plush as the BMW X2, but it’s well-equipped, functional and feels sturdy enough to last as long as you might need. It should also hold up well if you come to sell it, with a higher predicted value than many other sports SUVs.
Read our full Cupra Ateca review
Strengths
- Surprisingly smart interior
- Refined engine
- Great towing ability
Weaknesses
- Bouncy, uncontrolled ride
- Rivals have bigger load bays
- Shortage of modern safety kit
WLTP MPG 31.7mpg | Real MPG Average 29.0mpg | Town 20.5mpg | Motorway 28.7mpg | Rural 37.2mpg
Bearing the name Ssangyong up until 2023, the Korean car manufacturer KGM produces this keenly-priced pick-up truck, the Musso, and for a car that undercuts most rivals on price, it’s surprisingly impressive.
One of the Musso’s greatest strengths is its towing ability: its capacity of up to 3500kg puts it up there with the most muscular pick-ups.
The Musso’s interior is pleasantly smart, too, with plenty of soft-touch plastics you wouldn’t necessarily expect for a car at its price point. However, what you save on buying the Musso might come back to bite you when it comes to refuelling, having returned a measly average of 29.0mpg in our testing. As far as pick-ups go, only the Ranger Raptor performance model performed worse.
Read our full KGM Musso review
Strengths
- Big boot
- Impressive interior space
- Relatively agile for a family SUV
Weaknesses
- Interior quality not up to usual Audi standards
- Firmer ride than some rivals
- Fiddly infotainment system
WLTP MPG 31.7mpg | Real MPG Average 29.5mpg | Town 23.0mpg | Motorway 28.4mpg | Rural 36.3mpg
Like most of the other models on this list, this version of the Audi Q3 is designed more for performance than sheer efficiency – and it certainly fulfills the brief, thanks to its hefty 242bhp turbocharged 2.0-litre petrol engine which can slingshot it from 0-62mph in just 5.8sec.
And the Q3 doesn’t excel in just thrills; it’s also extremely practical and spacious inside, with sliding rear seats that allow you to maximise boot space or leg room depending on your needs. In fact, with the seats slid forward, the Q3 provides a huge 675 litres of boot space, which is even more than what you get in most large SUVs, such as the BMW X5 and Range Rover Sport.
While fuel economy leaves a lot to be desired, the Q3 is comfortable to drive, and more agile than most other family SUVs, but you’ll find that some rivals, like the Volvo XC40, are more plush.
Read our full Audi Q3 review
Our pick: 1.0 EcoBoost Hybrid mHEV Titanium 5dr
Strengths
- Well equipped
- Great driving position
- Even more fun with the grippy Track Pack
Weaknesses
- Infotainment system can be fiddly to use
- Interior is a bit low rent
- Steering is inconsistently weighted
WLTP MPG 35.3mpg | Real MPG Average 29.6mpg | Town 21.2mpg | Motorway 29.5mpg | Rural 37.2mpg
The performance-focused ST variant has been a staple in all four generations of the Ford Focus over the years, and its competitive pricing means that it has remained a solid option for drivers who are looking for a bit more fun without breaking the bank. Despite that, it will cost you more than most rivals to run.
At the heart of its perky performance is its 276bhp 2.3-litre petrol engine, which whisks the ST from 0-62mph in just 5.7sec. You’ll get similar speeds in the Hyundai i30 N and Volkswagen Golf GTI, and it’s more agile than the Cupra Leon.
Like other variants of the Focus, the ST benefits from a roomy interior, particularly when you buy an estate version. However, some of the materials do feel quite low-rent, although sporty details such as the red stitching, alloy pedals and ST-engraved stainless steel scuff plates on the sills give it points for charm.
Read our full Ford Focus ST review
Our pick: 420i M Sport 2dr Step Auto
Strengths
- Range-topping M440i is seriously rapid
- More fun to drive than direct rivals
- More room in the back than you might imagine
Weaknesses
- Some road noise at speed
- Back seats don't split and fold down
- Lots of options that could quickly drive up price
WLTP MPG 34.4mpg | Real MPG Average 29.6mpg | Town 20.2mpg | Motorway 29.6mpg | Rural 38.7mpg
There’s a lot to like about the BMW 4 Series Convertible, and this particular M440i version certainly doesn’t disappoint with its rapid pace, soulful engine sounds and exceedingly comfortable drive. It won’t save you much money at the petrol station, though, having returned an average of just 29.6mpg in our testing.
It’s not likely you’ll be thinking too much about fuel costs on the open road though, because the 4 Series provides a much more fun and involving drive than rivals such as the Mercedes CLE Cabriolet. And, despite its extra weight compared with its coupé sibling, it handles with surprising agility.
The rival Porsche 718 Boxster is more enjoyable, but the 4 Series trumps it in practicality, with seating for four adults and a decent-sized boot. On top of that, the 4 Series also benefits from a high-quality interior and responsive infotainment system.
Read our full BMW 4 Series Convertible review
Strengths
- Smooth and punchy engines
- High-quality interior
- Tidy handling and good ride in the right spec
Weaknesses
- Potentially firm ride on S line Sport suspension
- Not as practical as cheaper Q5
- Fiddly touchscreen infotainment system
WLTP MPG 32.1mpg | Real MPG Average 29.8mpg | Town 22.3mpg | Motorway 28.5mpg | Rural 38.3mpg
This sporty sibling of the Audi Q5 SUV is available with both petrol and diesel power, but we found that the 45 TFSI’s 2.0-litre petrol engine was the thirstiest. That being said, it’s more sprightly than the diesel alternative, shaving a second and a half off the latter’s 0-62mph time.
The Q5 Sportback benefits from some tidy handling and pleasantly precise steering, though some rivals such as the BMW X4 are slightly more refined. Still, it’s impressive for an SUV of its size, with plenty of grip, tight control and only a small degree of lean in the bends.
Inside, high quality materials decorate every surface, bringing a sense of class that is unbeatable by other rivals. However, the infotainment system is reliant on touchscreens, which can be distracting and unintuitive. If you’re a fan of rotary controllers and physical buttons, you’ll get along better with the iDrive system in the X4.
Read our full Audi Q5 Sportback review
Our pick: 2.0 TDI Life 5dr DSG
Strengths
- Exceptionally good predicted residual values
- Good value against van-based MPV rivals
- Lots of safety tech
Weaknesses
- Infotainment not the best
- No rear air-con as standard
WLTP MPG 31.4mpg | Real MPG Average 30.4mpg | Town 21.6mpg | Motorway 29.8mpg | Rural 39.6mpg
Like the Q5 Sportback, we found this petrol version of the Volkswagen Multivan to guzzle more fuel than the diesel alternative, but its 201bhp power output is punchy and will whisk you up to motorway speeds much faster.
Naturally, the Multivan excels when it comes to practicality, with masses of space for everyone to stretch out, and room for some smaller bags in the boot even with all the seats in place. Combined with a comfortable driving position and supportive seats, the Multivan really is quite pleasant inside.
While the Multivan is pricier than other MPV rivals, including the Ford Galaxy and VW Touran, it has extremely good predicted residual value, which might offset those high running costs.
Read our full Volkswagen Multivan review
Our pick: 2.2 D 210 Sprint 5dr AWD Auto
Strengths
- Good to drive
- Rotary controller for infotainment
- Responsive automatic gearbox
Weaknesses
- Rear space not as generous as rivals
- Fidgety low-speed ride
- Noisy diesel engines
WLTP MPG 33.2mpg | Real MPG Average 30.9mpg | Town 23.0mpg | Motorway 29.5mpg | Rural 40.0mpg
While it scored an impressive 40mpg in the rural portion of our test, the Alfa Romeo Stelvio’s real-world average was let down by its poor urban and motorway figures. So, if you spend a lot of your time pootling around the city or travelling on faster highways, then the Stelvio is best avoided.
That being said, you might be able to forget about those high running costs given how enjoyable the Stelvio is to drive. For a big SUV, it corners with surprising agility, and it can race from 0-62mph in just 5.7sec. However, it suffers from a pretty firm ride, so you’ll find yourself jostled around more than you would in rivals such as the Mercedes GLC.
Interior space isn’t a strong suit, though. The Stelvio’s sloping roofline means rear head room is rather lacking, but the boot is a decent size, and should provide for all the basic needs of a family.
