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GB1.6 t Typical car, per year

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Car CO₂ calculator

The number on your V5C is what the car emits per kilometre in a lab. This is what your actual driving emits in a year.

Your emissions

Your last two MOT certificates give this exactly
Real-world, not the brochure figure
0 kg a year

    How it works

    • Petrol: 2.075 kg CO₂e per litre. Diesel: 2.584 kg per litre. Both are the UK blended-fuel figures, so they include the bioethanol in E10.
    • Electric: 0.131 kg CO₂e per kWh — the average UK grid in the 2026 factors. It has fallen by about a quarter in a year as the grid decarbonises, and it is an average: charging overnight on a windy night is cleaner than a still evening.
    • This counts the fuel or electricity only, not the emissions of making the car. On that basis a new car always looks worse than keeping the one you have for another few years.
    Why mileage beats efficiency

    Cutting 2,000 miles a year removes roughly a fifth of the emissions of a typical car — more than swapping a 42mpg car for a 50mpg one. It also saves about £940 at 47p a mile. Twelve ways to do it.

    Next

    Petrol vs electric

    Cost per mile, your tariff.

    Compare

    Car tax

    Your CO₂ sets the first-year bill.

    Calculate

    Drive less

    The cheapest and cleanest mile.

    Read

    Sources: conversion factors — UK government greenhouse gas conversion factors 2026 (petrol 2.075 and diesel 2.584 kg CO₂e/litre, grid electricity 0.131 kg CO₂e/kWh). Last reviewed September 2026.