Carbon footprint calculator
Estimate your household's annual carbon footprint from energy, driving, flights and diet, with published emission factors.
Emission factors sourced from the EPA, UK DESNZ, and peer-reviewed research. See the methodology page for details.
For comparison, the US average is about 14.2 tonnes CO2 per person per year (Our World in Data (Global Carbon Budget), US per-capita fossil CO2 emissions, 2024). That average counts per-person fossil CO2, a narrower measure than this calculator's CO2e estimate.
Your electricity use alone is roughly $2,033.64 a year at the current US average rate.
Factors: electricity 0.3497 kg/kWh (EPA eGRID), gas 5.3 kg/therm (EPA), gasoline 8.887 kg/gallon (EPA), flights and diet per methodology page.
Enter your household figures for each category. The defaults represent a typical two-person US household with one car and gas heating. Adjust each field to match your situation.
Electricity emissions use the EPA eGRID national average grid intensity of 0.3497 kg CO2eper kWh. Your actual emissions may be lower if your utility uses more renewables or higher if it relies heavily on coal. Check your utility's fuel mix disclosure for a more precise figure.
The flight figures are derived from UK DESNZ per-km emission factors, assuming average return trip distances for short-haul (under roughly 3 hours) and long-haul categories, with radiative forcing included. A short round trip is estimated at 0.25 tonnes CO2e; a long-haul return at 1.1 tonnes CO2e.
Diet categories are broad estimates informed by published research. The figures cover food production and supply chain emissions, averaged across each diet type. Individual choices within a diet category can shift the actual figure considerably. The "average" preset reflects a typical US mixed diet.
Electricity: kWh per month x 12 x 0.3497 kg/kWh (EPA eGRID) / 1000. Gas: therms per month x 12 x 5.3 kg/therm (EPA) / 1000. Driving: (cars x miles per year / MPG) x 8.887 kg/gallon (EPA) / 1000. Flights: flight factors are derived from UK DESNZ per-km factors assuming average return trips, including radiative forcing uplift. Diet: diet figures are estimates informed by published research; they are not direct source line items. All emissions expressed in tonnes CO2e per year.
Full formulas and data sources are on the methodology page.
Frequently asked questions
- What is a carbon footprint?
- A carbon footprint is the total greenhouse gas emissions caused by an individual, household, or activity, expressed in tonnes of CO2 equivalent (CO2e). It includes direct sources like driving and gas heating as well as indirect sources like the electricity you buy and the food you eat.
- How accurate are the diet estimates?
- Diet figures are estimates informed by published research into food-system lifecycle emissions. They are averages across diet types and cannot account for individual food choices, regional supply chains, or food waste. They give a useful order-of-magnitude comparison between diet categories.
- What is radiative forcing and why does it affect flight emissions?
- Aircraft emit water vapour and other non-CO2 pollutants at altitude that have additional warming effects beyond their CO2 alone. Radiative forcing (RF) is a multiplier that accounts for this. The flight factors here are derived from UK DESNZ per-km factors assuming average return trips, and include an RF uplift.