Carbon Footprint Calculator calculates your CO2. Carbon Footprint refers to the amount of carbon dioxide, or CO2, a person generates through their activities. These activities include such things as transportation (driving, flying, riding a bus, etc.) and energy use (lights, electricity, etc.). It can also include indirect activities like going to a restaurant, throwing trash away, or even eating food. This is because when you go to a restaurant your presence there is causing more energy to be used and, therefore, more carbon generated.