Best MPG - diesel cars

When buying a new car, finding one with good fuel economy will reduce your fuel costs and tax bill. The list below shows the diesel cars with the best MPG that are available to buy as new in UK in 2021.
All three types of official MPG are shown (combined, urban and extra-urban) plus 'Real MPG'. This last figure is calculated by Next Green Car using a number of data sources - including real-world fuel economy data from Emissions Analytics - to more closely reflect an achievable miles per gallon figure for these diesel vehicles.
Select another search option to see more listings of cars with good fuel economy, or use the main car search to find used cars or filter by more criteria.
Diesel cars fuel economy
The official MPG figures for all vehicles, including diesel models are derived from the NEDC test. There are two parts to the test: an 'urban' cycle designed to reflect driving in a city environment with many stops and starts and an 'extra-urban' cycle designed to mirror more steady state motorway and country routes. The 'combined' figure, which is the most often quoted figure is an average of 'urban' and 'extra-urban' weighted by the distances covered in each test.
Often drivers find that it is difficult to achieve the official MPG figures, and it is well understood that these rates should be used as a comparison rather than a target to achieve. Next Green Car has estimated a 'Real MPG' figure which reflects real-world conditions more closely. See the real MPG page for more info.
Different diesel models can have dramatically different fuel economy, so before purchase it is essential to research into each model carefully to ensure a good fuel economy, with the resultant reduced fuel bills and car tax. High MPG is directly linked to lower tail-pipe CO2 so a diesel vehicle with good MPG will also emit a lower level of CO2 emissions into the environment.