Personal Carbon Footprint Calculator
Estimate your annual carbon footprint in tonnes of CO2 from home energy, driving, flights, and diet.
What this calculates
Carbon footprint is the annual greenhouse-gas emissions attributable to your lifestyle, expressed in tonnes of CO2-equivalent. Most personal footprints break down into housing energy, transport, food, and consumption. This calculator estimates the first three from rough inputs to give you an honest number to work with.
Formula & how it works
Annual CO2e = home_kwh × 0.4 kg + gas_therms × 5.3 kg + car_miles × 0.36 kg + flight_hours × 250 kg + diet_factor. Diet factors (tonnes/year): heavy meat 3.3, average omnivore 2.5, low meat 1.7, vegetarian 1.4, vegan 1.0. World average per person: ~4.5 tonnes. US: ~16 tonnes. EU: ~7 tonnes.
Worked example
5,000 kWh electricity + 500 therms gas + 10,000 car miles + 30 flight hours + average omnivore diet. = 2.0 + 2.65 + 3.6 + 7.5 + 2.5 = 18.25 tonnes/year. That's well above the world average. Switching diet to vegetarian and halving flights drops to 14.4 tonnes — meaningful.
Frequently asked questions
Should I focus on individual action?
Mixed evidence. Individual choices add up across millions of people, and big-ticket items (flights, car choice, home heating) really matter. Policy and corporate action drive bigger structural changes.
What's the biggest lever?
For most people: flights, car ownership/use, home heating, and meat. A single transatlantic flight ≈ 1 tonne. A year of beef-heavy diet ≈ 1.5 tonnes more than vegetarian.
Is offsetting worth it?
Quality varies wildly. Reforestation projects have mixed track records. Direct-air-capture is rigorous but expensive ($300+/tonne). Many cheap offsets are essentially symbolic. Best to reduce first.
What's a 'good' footprint?
To stay within Paris targets, the global average per capita needs to fall to ~2 tonnes by 2050. Currently ~4.7. Most rich-country residents have a long way to go.