Our True MPG tests tell you what sort of mpg you can expect from your car in the real world.
While the figures published in sales brochures can help to tempt you into a new car, those results can be misleading.
What Car?'s True MPG tests are conducted on a rolling road under strictly controlled laboratory conditions. The route our cars drive is based on real-world driving data across a selection of road types. In short, although the cars are driven in a lab, they're following a real road route we've picked out.
But which are the best performing cars we've tested so far, and which have fallen far short of the manufacturer's claims? In this article, we'll be looking at small cars and city cars - an area of the market where low running costs, including fuel economy, is vital.
In each case below, we've noted the official claimed fuel economy of each car, its True MPG result, and the percentage disparity between the two. Read on to find out which are the top performers, and which will leave you sitting at the pumps most often.
The most (and least) efficient city cars and small cars
10. Renault Twingo 0.9 TCe
Official combined mpg: 57.7 True mpg 47.5 % difference 17.7%
The latest Renault Twingo majors on its stylish looks, but its True MPG rating is pretty far adrift from its official fuel economy figures. This 0.9-litre petrol engine also feels underpowered in the Twingo, and it has to be revved hard to perform - further denting your real-world mpg.
9. Hyundai i10 1.2
Official combined mpg: 57.6 True mpg 49.3 % difference 14.4%
We named the Hyundai i10 as our City Car of the Year at the most recent What Car? Awards, and that's because when it comes to small cars with big space inside, nothing beats it. The i10 is also quieter than most of its rivals, has a class-leading infotainment system on our recommended Premium SE trim, and its 1.2-litre petrol engine has enough power to cope with motorway jaunts.
Official combined mpg: 54.3 True mpg 49.5 % difference 8.8%
The Ibiza competes in the same market as the best-selling Ford Fiesta and Vauxhall Corsa, and it shares most of its parts with the VW Polo. It's a strong performer, offering good levels of equipment and low running costs, but the engine we ultimately recommend is the 1.0 EcoTSI 95 rather than the 1.2-litre petrol tested here.
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