5 brilliant fuel-efficient diesel cars to buy in 2025
Here are the most economical diesel cars on sale in 2025 to save you money on fuel
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Searching for the most economical diesel cars is a rite of passage for anyone interested in seriously efficient driving.
They’ve always been a great pick if you want to save on fuel, but diesel cars aren’t praised as much as they used to be.
Even with electric and hybrid cars on the rise, there’s something about a familiar diesel drive that’s hard to forget.
If you still love an efficient diesel, take a look at our list of most economical diesel cars below.
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Best mpg diesel cars
A car’s fuel economy will vary depending on who’s behind the steering wheel because we all have different driving styles.
However, the following diesel cars are listed by their official average fuel economy rating, measured using the WLTP (worldwide harmonised light-duty vehicles test procedure).
Mercedes-Benz E300 de – 201mpg
Peugeot 208 1.5 Blue HDi – 71.4mpg
Vauxhall Corsa 1.5 Turbo D – 70.6mpg
Skoda Octavia 2.0 TDI SE – 64.2mpg
Volkswagen Golf 2.0 TDI – 64mpg
Audi A4 35 TDI saloon – 60.1mpg
SEAT Leon 1.6 TDI – 57.6mpg
Ford Mondeo 1.0 TDCi 180 – 56.1mpg
Read more about each car below.
Mercedes-Benz E300 de – 217.3mpg
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No, we haven’t made a mistake – the E300 de really does have a frankly astonishing official economy figure.
Okay, so we’re cheating a bit since this is a hybrid diesel but, firstly, hybrid diesels are pretty rare and, secondly, 201mpg is too impressive to not mention.
You’ll need to keep the car’s battery topped up to achieve these economy levels. And you also get 33 miles of electric-only range if you don’t want to worry about mpg at all.
It’s one of the most economical diesel cars on the market, and it’s genuinely enjoyable to live with, as you’d expect from a Mercedes.
We love the suave styling of the car, and its high-tech interior with two large screens is one of the best around.
Peugeot 208 1.5 Blue HDi – 71.4mpg
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Launched in 2019, the Peugeot 208 is one of the sharpest superminis out there.You get five doors, fancy LED lights and a 1.5-litre diesel engine that’ll return more than 70mpg, officially.
The baby Peugeot’s interior is equally interesting, with a very stylish dashboard including instruments that you view over the steering wheel, rather than through it.
Sam Sheehan, our motoring editor, tried the 208 for himself and said: “There’s lots to love about the Peugeot 208, from its looks to the comfortable ride that it provides.
“It also gives drivers the distinct feeling that they’re in a much more luxurious car than they really are, thanks to the beautifully styled interior.”
Vauxhall Corsa 1.5 Turbo D – 70.6mpg
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It’s no coincidence that the 2019 Corsa shares its good looks with the Peugeot – both brands fall under the Stellantis umbrella – and both are among the most economical diesel cars on the market.
The Vauxhall Corsa also shares the Peugeot’s engine, which explains why its economy figure is so similar.
The main difference between this used Vauxhall and the Peugeot above is its styling, which is subjective, so you can choose whichever you think looks the best.
Skoda Octavia 2.0 TDI SE – 64.2mpg
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Just about any version of the Octavia is a cracking family car, thanks to masses of interior space (including a huge boot, especially on the Estate model), but this version also adds terrific economy to its repertoire.
And you can add that it’s cheap to buy, as well as cheap to run, to its list of positives.
This used Skoda estate doesn't have the most powerful engine, but it has a lot of torque. It’s ideal for eating up motorway miles and you still won’t need to change down to overtake.
For the stats, expect 0-62mph in 8.5 seconds that feels peppy at the traffic lights. It’s one of the most economical diesel cars and it’s a truly enjoyable drive.
Volkswagen Golf 2.0 TDI – 64mpg
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A bit like the Peugeot and Vauxhall, above, the Skoda and VW share many parts.
This version of the Mk8 Golf has the same 150hp diesel engine and six-speed manual gearbox as its Octavia cousin, wrapped in understated and classy VW styling.
It’s not as roomy as the Octavia inside, but it feels more premium, with digital instruments on most versions and a large infotainment screen with Apple CarPlay and Android Auto connectivity.
Plus, you can also find used Volkswagen models at impressive prices.
Audi A4 35 TDI saloon – 60.1mpg
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Choosing one of the best mpg diesel cars doesn’t mean you have to skip the premium brands, and the Audi A4 is a great option.
It’s a comfortable car with plenty of that handsome Audi charm, and the interior is luxurious and filled with tech.
It’s obviously an efficient choice, but can still hit 0-62mpg in 8.2 seconds – though we recommend keeping it calm and steady on the road if you want to save on fuel.
Sam road-tested the A4 and said: “The Audi A4 is simply one of the best executive cars out there, no question.
“It makes most journeys pass without causing any negative impact on your day, and no matter which version you choose, it’ll have loads of kit to keep you comfortable and entertained.”
SEAT Leon 1.6 TDI – 57.6mpg
 "SEAT Leon front")
The SEAT Leon is a suave all-rounder that’s a top family hatchback pick and can be one of the most economical diesel cars on the market.
The 1.6 TDI model is ideal for savouring your diesel reserves, but it also offers low road tax and insurance to complete a trio of low running costs.
It’s easy to drive and spacious, with a 380-litre boot that expands to 1,470 litres if you fold down the seats.
Ford Mondeo 1.0 TDCi 180 – 56.1mpg
 "Ford Mondeo front")
The Ford Mondeo is a great value option if you’re after the best mpg diesel car that can really do no wrong.
It’s spacious, comfortable, easy to drive and even easier on the eye. The 56.1mpg WLTP figure isn’t the best on this list, but it’s still a highly respectable stat.
Sam said: “The Ford Mondeo is a car designed to take you from one end of the country to the other without breaking a sweat.
“No matter which engine's under the bonnet, it absolutely chomps through miles, and you’ll get to the far end of your journey feeling pretty much as fresh as when you first sat down.”
Why are diesel cars better now?
Two things have helped diesel cars clean up their act: particulate filters (known as DPFs) and diesel exhaust fluid.
A DPF collects the soot that’s produced by burning diesel and stops most of it being emitted from the tailpipe.
This collected soot is periodically burnt off at very high temperatures, which is less damaging to the environment.
Diesel exhaust fluid – also known as AdBlue – is used to reduce a diesel car’s nitrogen oxide (NOx) emissions.
It’s automatically injected into the exhaust system after the DPF to convert much of the NOx to nitrogen and water.
Diesel cars with this emission-reducing tech have a Euro 6 emissions rating, and all new diesel cars sold from September 2015 have had to be Euro 6-compliant.
Why were diesel cars so popular?
The UK government decided to change the taxation system in the early 2000s to a carbon dioxide-based ranking.
This is because when burned, diesel emits almost half of the CO2 compared with the same amount of petrol – great news for our fight against climate change.
Back then, however, without emissions-reducing tech, diesel vehicles were emitting a lot more particulates and NOx than petrol engines, which were bad for human health.
While CO2 has a global impact, NOx and particulates affect those around the car since both are breathed in and can cause long-term health issues.
It wasn’t long before the EU brought in regulations to tighten up diesel emissions, and we’re now at Euro 6, introduced in September 2014.
The latest version of this is Euro 6d, which applied to all new cars from January 2021.
The car industry’s trade body in the UK, the Society of Motor Manufacturers and Traders (SMMT), said: "It would take 50 new cars today to produce the same amount of pollutant emissions as one vehicle built in the 1970s – which just goes to show how far we’ve come.”
Buying the most economical diesel cars
It’s a tempting list, right? These best mpg diesel cars were made to make your life easier by keeping running costs low.
What’s better is that you can find great deals by choosing a pre-owned model. Take a look at our full range of used diesel cars to find a great deal.
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