Estimate your annual CO2 emissions from transportation, home energy, and lifestyle.
This calculator estimates your personal carbon footprint across three major categories: transportation (driving and flying), home energy (electricity and heating), and diet. It uses emission factors from the EPA and EIA to convert your inputs into metric tons of CO2 equivalent per year.
Driving emissions are calculated from your annual mileage and fuel efficiency using the EPA's figure of 8.887 kg CO2 per gallon of gasoline. Flight emissions use an average of 0.25 kg CO2 per passenger-mile, which includes the radiative forcing multiplier (the additional warming effect of emissions at altitude). Home energy conversions use the national average grid emission factor and natural gas emission rates. Diet estimates are based on lifecycle analysis studies of food production by dietary pattern.
The average American produces about 16 metric tons of CO2 per year, roughly 4 times the global average of 4.7 tons and more than double the European average. The breakdown varies by individual, but transportation typically accounts for the largest share (about 29% of U.S. emissions), followed by electricity (25%), industry (23%), and agriculture (10%).
Within personal emissions, the biggest contributors are typically: driving (4-6 tons for the average commuter), home electricity and heating (3-5 tons depending on region and home size), flying (0.5-3 tons depending on frequency), and diet (1.5-3.3 tons depending on meat consumption).
Transportation is usually the largest category. Switching from a 25 MPG car to a 50 MPG hybrid cuts driving emissions in half. An EV charged on average U.S. grid electricity produces about 60% less CO2 than a gasoline car. Carpooling, biking, or taking public transit for commuting can eliminate 1-3 tons per year.
Flying is the most carbon-intensive activity per hour. A single round-trip cross-country flight (New York to LA) produces about 1 metric ton of CO2 per passenger. For frequent flyers, air travel can easily be the single largest source of personal emissions. One fewer flight per year makes a measurable difference.
Home energy depends heavily on your region. Homes heated with oil or propane produce more CO2 than those using natural gas. Electricity emissions vary dramatically by state: a kilowatt-hour in coal-heavy West Virginia produces 5-6x more CO2 than one in hydro-powered Washington state. Improving insulation, sealing air leaks, and upgrading to a heat pump can cut home energy emissions by 30-50%. Use our Electricity Cost Calculator to see what your appliances actually cost to run, and see our guide to lowering your electric bill for practical tips.
Diet matters more than most people think. Beef production generates roughly 10x the emissions of chicken and 20x the emissions of plant proteins per gram of protein. Cutting beef consumption in half reduces diet-related emissions by about 0.5 tons per year. Going fully vegetarian saves about 1 ton. Going vegan saves about 1.5 tons compared to the average American diet.
Emission factors: EPA Greenhouse Gas Equivalencies Calculator, EIA Monthly Energy Review. Flight emissions: ICAO Carbon Emissions Calculator methodology. Diet lifecycle data: Poore and Nemecek (2018), "Reducing food's environmental impacts through producers and consumers," Science. U.S. and global averages: World Bank CO2 emissions per capita data (2022).