How the carbon footprint calculator works
Enter your driving, home electricity and gas use, and flights, and the tool estimates your yearly carbon dioxide emissions in tonnes. It applies average emission factors to each activity, adds them up, and splits the total by household size. It also estimates how many trees it would take to absorb that much carbon in a year.
What the estimate includes
The calculator covers the biggest household sources: petrol or diesel driving, grid electricity, natural gas heating, and air travel. It uses representative factors, roughly 8.9 kilograms of carbon dioxide per gallon of gasoline, around 0.4 kilograms per kilowatt hour of electricity, and about 5.3 kilograms per therm of gas. Flights are approximated per round trip.
Why your real number varies
Emission factors differ a lot by place and circumstance. A grid powered by hydro or nuclear emits far less per kilowatt hour than one burning coal, and flight emissions depend heavily on distance and class. Treat this as an order of magnitude estimate to compare choices, not a precise or official figure.
Using it to cut emissions
Change one input at a time to see which choices move your total most. For many people, driving, flights, and home heating dominate, so shifts there, like driving less, flying less, improving insulation, or switching to cleaner electricity, have the biggest effect. The trees figure is a rough offset reference, not a substitute for reducing emissions.
Frequently asked questions
How big is an average footprint? It varies hugely by country; some high consumption nations average over 15 tonnes per person a year.
Is this an exact measurement? No, it is a rough estimate using average factors; your grid and travel patterns change the result.
What reduces a footprint most? Usually less driving and flying, better home efficiency, and cleaner electricity.
Related calculators: Electricity Cost, Tree Offset, Solar Panel.