Revealed: the truth about electric car range

It’s an issue drivers of petrol and diesel cars will be all too aware of: a car’s advertised fuel economy is far better than what you actually end up getting. This same problem exists for electric cars.

If you’re in the market for an electric car, its range (how far the car can go between charges) is likely to be one of the first things you look at. This is especially true if you don’t have the ability to charge at home.

The claimed range from official WLTP (Worldwide Harmonised Light Vehicle Test Procedure) tests may look enticing in the showroom, with some models now claiming in excess of 400 miles between charges.

But in our tests, we found the actual range of an electric car to be on average 18% less than the official figure. That means an electric car with a claimed 240-mile range (the average claimed WLTP range from cars we’ve tested since 2017) is more likely to offer a maximum range of around 196 miles.

Some cars are significantly worse. When we originally tested the dual motor 'long range' version of the Polestar 2, it had a claimed WLTP range of 298 miles but delivered just 183 miles in our tests. That's a colossal loss of 115 miles (39%) of range compared to the official claim.

Polestar has since released over the air updates and vastly improved the car's range. After re-testing the same car, we found it's tested range is now a much improved 247 miles, but it's still far off the (also increased) official range of 302 miles (18% less than claimed, bringing the car in line with the average electric car).

The current BMW iX (2021-) bucks the trend, though. Our tests on the xDrive50 version of the iX show that it can travel a record-breaking 382 miles before running out of juice - that’s two miles more than the official WLTP figure. 

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The best and worst cars at delivering their WLTP range

Range in an electric car is primarily based on the capacity of its battery and how efficient that car is. It is also then influenced by factors including weather (batteries do not like the cold), driving style and speed. You’ll get fewer miles of range on the motorway compared to driving around town.

Since 2017, the official range tests carried out by manufacturers use the WLTP cycle. This replaced an old test cycle called the NEDC, and is a much improved assessment. But while regular petrol and diesel cars now have more realistic fuel economy figures, we’ve found that the WLTP cycle has a strong tendency to overstate the efficiency and subsequent range of electric vehicles (EVs), when compared to our own tests - and that figure can vary significantly.

Taking the pre-updated Polestar 2 as an example, the dual motor version might currently represent the biggest difference between official (298 miles) and range in our tests (183 miles). But the single motor version of the same car is significantly better.

With a single motor, the Polestar 2 has an official WLTP range of 335 miles, and delivered an impressive 298 miles in our tests (so just 11% less than claimed) - it's a fantastically usable car in this guise. On paper the claimed ranges are less than 40 miles apart, but the range we got in our tests differs by over 100 miles.

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Differences like this highlight why our independent lab tests are so important. Our tests are tough, realistic and comparable. Every electric car we receive goes through the same tests in the same conditions, and includes a mix of simulated driving from city to motorways. You'll find the tested range of every electric car we've tested in our reviews.

We last updated our test programme in 2017, all figures in this news story are from the 60 electric cars we've tested under the current programme.

The three cars that got closest to their official ranges in Which? tests:

And the three worst:

Range is just one aspect you need to consider when buying an electric car. Find out what else you need to know by listening to our Which? Shorts podcast.

What you can expect from different electric car classes

Battery size doesn't just affect range, it also has a large influence on the cost of the car.

While there are exceptions, you’ll typically find bigger batteries in larger and more expensive cars paired with enticingly long claimed ranges. 

This table shows the different classes of electric car we’ve tested, their average claimed and tested range, and the differences.

*Typically hatchbacks

Which? car expert Adrian Porter says 'This is not an unknown issue. Lease companies and even some car manufacturers will publish a more realistic range figures in addition to the claimed WLTP range to give their customers a better idea of how far they'll actually travel between charges.

'The WLTP has improved the accuracy of petrol and diesel fuel economy. But when it comes to electric cars and plug-in hybrids, a more accurate official methodology of measuring the car's efficiency and subsequent maximum range, ideally with estimates of how that figure varies on different roads and temperatures, would be welcome.'

You can find out how we want to shape electric car charging by reading our paper on building an Electric Vehicle Charging Infrastructure that is Fit for the Future.

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