What are the CO2 emissions of my car?

4 minute read

Line of motorway traffic viewed in car wing mirror

Our cars can produce a significant amount of carbon dioxide in their lifetime, and knowing this information could help you to understand how you can reduce your car’s carbon footprint. Below, we reveal just how much CO2 our cars can produce, as well as how you can find out what your particular model could create

How much CO2 does a car produce?

The amount of CO2 a car produces depends on its age (older cars are less efficient), the type of fuel it uses, and more. However, you can take the below as a general guide to get an idea of the emissions it’s creating per year.

The below figures are based on a vehicle driving 7,600 miles in a year, the UK average:

  • Petrol cars - 1749kg (1.7 imperial ton)
  • Diesel cars - 2006kg (1.9 imperial ton)
  • Hybrid vehicle - 1544kg (1.5 imperial ton)
  • Plug-in hybrid - 429kg (0.4 imperial ton)

All Battery Electric and Fuel cell Electric Vehicles are zero emission [1].

To put the figures above into perspective, 500kg is the equivalent of a return plane journey from London to Glasgow.

While standard petrol and diesel cars are at the top of the chart, electric cars may not be as low-emission once you take into account battery production.

According to the Department for Transport, the production emissions for Battery Electric Vehicles (BEVs) are around 50% higher than petrol cars in 2020 (mainly due to the batteries) [2]. However, this same report estimates that by 2050 BEV production emissions could reach close to parity with those of conventional vehicles. 


How does CO2 affect road tax?

Every year, the vehicle excise duty (VED), commonly known as road tax, increases with inflation. The amount of road tax you pay is based on how much CO2 your vehicle emits. Generally, the more CO2 your car emits, the more you pay.

The CO2 emissions of a vehicle are measured in grams per km (g/km). If we apply this measurement to the averages listed above, it will work out as:

  • Petrol cars - 143.0 g/km
  • Diesel cars - 164.0 g/km
  • Hybrid vehicle - 126.2 g/km
  • Plug-in hybrid - 35.1 g/km

All Battery Electric and Fuel cell Electric Vehicles are zero emission [1].

Older and faster cars tend to emit more carbon. For instance, the Lotus Elise Sport has a rating of 173g/km and the Porsche 911, 242g/km. The higher the emissions, the more tax you will have to pay.

If you want to understand what is considered high or low in terms of petrol/diesel/hybrid emissions, here is a rough guide: 

  • 150g/km is considered low
  • 160 to 255g/km is considered medium
  • Above 255g/km is considered high

If your car was registered between 1st March 2001 and 1st April 2017, the tax will be based on the official CO2 emissions for that car. However, vehicles registered after 1st April 2017, are subject to a flat rate after the first year (the first year's 'show room' tax is still based on C02 emission levels). After year two, this rate will be £180 per year, unless your car has zero emissions, in which case, the car is exempt (though this exemption is set to be revoked in 2025).


How can I find out how much road tax I need to pay?

To find out the exact information for your own car, you can use the Vehicle Certification Agency’s tool. Simply answer their questions about the type of car it is, its fuel type and when it was registered and they’ll provide you with an accurate measurement.

Electric cars are noted as having 0g/km. This is because the cars themselves don’t produce any carbon. Instead, the electricity that is used to power them is created by mainly burning fossil fuels, and so this is where the carbon emissions for electric vehicles comes from. It’s also for this reason that electric vehicles don’t need to pay the Ultra Low Emission Zone (ULEZ) fee, which is a scheme to reduce emissions in the city of London.

You could use this information to help you choose your next car, opting for a model that’s more environmentally friendly over one that produces a lot of carbon. The more people that choose an eco-friendly model, the more we can bring down carbon emissions and protect our planet for future generations.


*Information correct as of 2023, based on 2022 averages. 


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