True MPG: which cars beat their official figures – and which are farthest away?

New petrol, diesel and hybrid cars are on average 8.2% less efficient in real-world conditions than the official WLTP figures suggest, What Car? has found.

We put 168 popular models through our independent True MPG test, with the worst performers 26.4% down on their official numbers, but 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% thirstier 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.

So, which of the latest models were farthest away from their official figures, and which over-achieved? Let's take a look, starting with the 10 biggest under-performers…

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Official WLTP average 56.5mpg True MPG 45.2mpg Difference 19.9%

Despite appearing on this list, the 3 Series is well worth considering, because it's fantastic to drive and has the most user-friendly infotainment system around. Bear in mind, though, that the 330e plug-in hybrid version makes a lot more sense than this 2.0-litre diesel model – particularly as a company car.

Read our full BMW 3 Series review

Official WLTP average 51.4mpg True MPG 41.1mpg Difference 20.0%

The latest Camry is a spacious executive saloon that comes well equipped. However, it suffers from a poorly controlled ride and the 2.5-litre petrol engine needs to be worked surprisingly hard at times. This latter issue probably contributes to the disappointing real-world fuel efficiency.

Read our full Toyota Camry review or see the latest Toyota Camry discounts

Official WLTP average 51.3mpg True MPG 41.0mpg Difference 20.1%

With its funky looks, the C3 does a great job of turning heads. However, in addition to falling around 10mpg short of its official economy in the form we've tested, it's poor to drive and not very practical. As a result, any number of small car rivals are more recommendable on an objective level.

Read our full Citroën C3 review or see the latest Citroën C3 discounts

Official WLTP average 43.5mpg True MPG 34.6mpg Difference 20.4%

If you think MPVs can't be fun to drive, the S-Max will force you to reconsider, thanks to its precise steering and excellent body control. And while the interior isn't as classy as some rivals', it is practical. Just don't expect the 2.5-litre petrol version to be a particularly frugal choice.

Read our full Ford S-Max review

Official WLTP average 50.4mpg True MPG 40.1mpg Difference 20.4%

The peppy performance of Nissan's 1.0-litre petrol engine impresses, even if its True MPG figure doesn't. But perhaps the Micra's biggest problem is that it's merely okay in most respects, despite competing in a class that's packed with talent.

Read our full Nissan Micra review or see the latest Nissan Micra discounts

Official WLTP average 44.1mpg True MPG 34.6mpg Difference 21.6%

While they're about as on-trend as safari suits, diesel engines can still make plenty of sense in large SUVs such as the XC60. However, the B4D is the Volvo diesel unit we'd recommend you look at, rather than the B5D that features here.

Read our full Volvo XC60 review or see the latest Volvo XC60 discounts

Official WLTP average 64.2mpg True MPG 50.3mpg Difference 21.6%

The Swace is essentially a rebadged version of the Toyota Corolla Touring Sports, and shares that car's hybrid engine. But despite being able to run on electric power for short distances, it was still far adrift of the official government fuel economy figure. More positively, it offers a comfortable ride and lots of standard kit.

Read our full Suzuki Swace review or see the latest Suzuki Swace discounts

Official WLTP average 34.8mpg True MPG 27.1mpg Difference 22.1%

Overall, the XC40 is the best family SUV on sale, because it blends generous passenger space and a practical boot with a quality feel and top-notch safety. The latest T4 model is even an efficient choice, unlike its predecessor, which averaged just 27.1mpg in our tests.

Read our full Volvo XC40 review or see the latest Volvo XC40 discounts

Official WLTP average 58.9mpg True MPG 45.5mpg Difference 22.8%

If you’re after an affordable coupé SUV that’s still pretty practical, the Arkana is worth a look. And a True MPG figure of 45.5mpg isn't overly disappointing – until you see how far that is from the official average.

Read our full Renault Arkana review or see the latest Renault Arkana discounts

Official WLTP average 57.6mpg True MPG 42.4mpg Difference 26.4%

Our reigning Coupé of the Year might be more fun to drive than its rivals and surprisingly practical, but there's no getting around the fact that the 420d diesel version was farther away from its WLTP average than any other car we've tested. We'd therefore go for the cheaper and sweeter-sounding 420i petrol.

Read our full BMW 4 Series review or see the latest BMW 4 Series discounts

Official WLTP average 55.7mpg True MPG 59.9mpg Difference +7.5%

This mild hybrid version of the Ignis averaged almost 60mpg in our tests, which is hugely impressive for a small SUV. Don't let the size of the Ignis fool you, though, because it's surprisingly spacious inside. We also like the long list of equipment on SZ-T models, with 16in alloy wheels, a rear-view camera and a touchscreen infotainment system all standard.

Read our full Suzuki Ignis review or see the latest Suzuki Ignis discounts

Official WLTP average 44.3mpg True MPG 47.7mpg Difference +7.7%

Dacia is all about cheap motoring, and the Logan lives up to that, not only with its purchase price, but also its running costs. Unfortunately, in many respects you get what you pay for, because the independent safety experts at Euro NCAP awarded the Logan just two stars, plus it's a noisy car and the driving position is compromised.

Read our full Dacia Logan review

Official WLTP average 40.5mpg True MPG 44.2mpg Difference +9.1%

The Karoq is basically the Seat Ateca’s less sporty sister, but this 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.

Read our full Skoda Karoq review or see the latest Skoda Karoq discounts

Official WLTP average 33.2mpg True MPG 36.3mpg Difference +9.2%

What's better than a car that's good to drive and surprisingly 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 quite noisy, though, and there are cheaper hot hatches.

Read our full Honda Civic Type R review or see the latest Honda Civic Type R discounts

Official WLTP average 39.8mpg True MPG 43.8mpg Difference +10.1%

The Duster already represents great value for money, even before you factor in that it beats its official fuel economy figure by more than 10% in real-world conditions. That means you can spend less time at the pumps and more time making the most of its spacious interior.

Read our full Dacia Duster review or see the latest Dacia Duster discounts

Official WLTP average 40.9mpg True MPG 45.1mpg Difference +10.3%

Sports cars and efficiency don't generally go together, but the MX-5 is both fun to drive and frugal, aided by its small size and low weight.

Read our full Mazda MX-5 review or see the latest Mazda MX-5 discounts

Official WLTP average 50.7mpg True MPG 56.0mpg Difference +10.5%

The Up is a good choice if you live in the city, offering nimble handling and a relatively classy interior. It's merely a very welcome bonus that this 1.0-litre petrol-engined version is also significantly more frugal than the official figures would have you believe.

Read our full Volkswagen Up review or see the latest Volkswagen Up discounts

Official WLTP average 42.2mpg True MPG 47.4mpg Difference 12.3%

Although two hybrids rank among the cars which fall well short of their official test results, the Honda CR-V shows that not all such models 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.

Read our full Honda CR-V review or see the latest Honda CR-V discounts

Official WLTP average 30.7mpg True MPG 35.2mpg Difference +14.7%

It probably won't shock you to learn that this pick-up truck has a bouncy ride and a noisy engine. However, the real-world economy that the D-Max is capable of will come as a pleasant surprise, while its payload ratings are as good as you'd hope.

Read our full Isuzu D-Max review

Official WLTP average 30.7mpg True MPG 36.5mpg Difference +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 of the Year, including its comfortable ride, gutsy engine and competitive pricing.

Read our full Ford Ranger review

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