CO₂ emissions from motor vehicles: the basics
Formula, emission factors and context
A vehicle’s CO₂ emissions depend directly on fuel consumption: each liter of petrol (E10) burned produces 2.37 kg of CO₂, each liter of diesel produces 2.65 kg of CO₂. The annual balance is calculated as: CO₂ (kg) = consumption (L/100 km) ÷ 100 × km per year × emission factor. For a typical vehicle with 7 L/100 km of petrol and 15,000 km/year, that is 1,050 liters × 2.37 kg/L = 2,488.5 kg of CO₂ – around 2.49 tonnes.
For comparison: according to the German Advisory Council on Global Change, the total personal CO₂ budget available to each person for a climate-neutral life is around 1–2 tonnes per year (across all sectors combined). For many people, the car alone therefore already uses up most or all of that climate-compatible budget, or exceeds it. Fuel-efficient driving, carpooling, or switching to a low-emission vehicle can significantly reduce this figure.
Note that this calculator computes tank-to-wheel emissions – meaning only the direct CO₂ output at the tailpipe, without emissions from fuel production and delivery (well-to-wheel). Including these upstream and downstream emissions raises the actual CO₂ equivalents by 15–25%. The EU CO₂ limits for new passenger car registrations likewise refer to tank-to-wheel values.