How exactly is the carbon footprint calculated?

The carbon footprint is calculated with the help of so-called CO2 factors. Ideally, there is such a factor for each product or activity, which has been scientifically determined and indicates how many kilograms of CO2 equivalents are emitted by using the product or carrying out the activity.

As an example: According to a source from the German Federal Environment Agency, a medium-sized car causes 0.214 kg of CO2 for a distance of one kilometer. Based on this, your carbon footprint is calculated using your data on the number of vehicles you have and your activities with them (kilometers driven on the way to work or school, on trips or to business appointments).