Peugeot 308 review - MPG, running costs & CO2

There’s bound to be a Peugeot 308 that suits your needs because there are petrol, diesel, mild-hybrid petrol and plug-in hybrid options, as well as the fully electric E-308. In general, we would recommend a petrol model to those who do a mix of motorway journeys and shorter trips around town, but the mild-hybrid is also a great option because it only costs slightly more but boosts fuel economy quite a bit.

Diesels work best for those doing a lot of long-distance drives, while plug-in hybrids are great for those with a short commute that can be done on electric power alone. The plug-in hybrid is also a good option for company-car drivers because of the low CO2 emissions figures. 

Peugeot 308 MPG & CO2

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The 1.2-litre three-cylinder petrol engine was a solid choice for the entry-level car, achieving up to 51.9mpg, while the mild-hybrid version of the same engine that arrived in 2024 can return up to 62.6mpg. While the standard petrol has CO2 emissions between 123g-147g/km, the mild-hybrid’s span 102-131g/km.

If you do a lot of long trips then you might consider the 1.5-litre BlueHDi diesel as an option. This engine emits 124-148g/km and returns between 50.1mpg and 59.6mpg on the combined WLTP test, so the higher figure should be realistic on a long motorway journey. Given it costs more than the mild-hybrid and doesn’t boast particularly high mpg figures in comparison, it’s hard to make a case for the diesel.

There are two plug-in hybrid models that use a 1.6-litre petrol engine and electric motor – despite two different power outputs, these get identical efficiency and emissions figures. CO2 emissions are between 26-32g/km depending on trim level, so they’re cheap to tax for company car drivers. It sits in a low tax bracket for Benefit-in-Kind, which is good but some rivals including the plug-in hybrid version of the SEAT Leon sit in even lower brackets, so they are even cheaper to tax.

Fuel economy is tough to work out for the plug-ins because it depends on usage – plug in every day and avoid using the engine at all costs and you could see up to 243mpg, according to Peugeot’s official figures, but that’s unlikely to be the reality for most. If you use the engine a lot, the economy figure could drop below that of the standard 1.2-litre petrol engine, because the engine also has to lug around a heavy battery. While the official EV range is 35-36 miles, we found around 30 to be more realistic in real-world driving. This is still a respectable figure, that should cover most commutes without consuming too much fuel.

Insurance groups

The standard petrol, mild-hybrid petrol and diesel engines span groups 19-21, which is a little higher than some family hatchbacks, perhaps because there’s no manual option. Plug-in hybrids start in group 26 and go up to 29 for the slightly more powerful version.

Warranty

All new Peugeots get a three-year/60,000-mile warranty, which is traditional for most manufacturers. If you want a family hatch with a longer warranty you could consider a Hyundai i30, a Kia Ceed or a Toyota Corolla, as those makers offer much longer factory warranties.

Servicing

Peugeot offers servicing plans that let you pay monthly instead of in a lump sum when servicing time comes. Some Peugeot dealers will even come and get the car from you and deliver it back, plus offer a video showing you what has been done.