You enter annual miles driven and vehicle MPG, monthly electricity in kWh, monthly natural gas in therms, and flight activity. The tool applies EPA and IPCC emission factors to each source: 19.6 lbs CO₂ per gallon of gasoline, the national average grid intensity for electricity, 11.7 lbs CO₂ per therm for gas, and a per-passenger-mile factor for flights. Diet, consumer goods, and indirect emissions are not included.
The U.S. per-capita average is roughly 16 metric tons of CO₂ per year, which is among the highest in the world. The global average is closer to 4–5 tons per person. Reducing driving and air travel tends to have the largest impact.
Driving, electricity, natural gas, and air travel are the four largest categories most people can directly measure and control. Diet, shopping, and supply-chain emissions are harder to quantify without detailed data, so they are excluded for simplicity.
It is a rough ballpark. A mature deciduous tree absorbs roughly 22 kg of CO₂ per year on average, but actual rates vary widely by species, age, soil, and climate. Carbon offset programs use more precise models, so treat this number as directional.
An EV eliminates tailpipe emissions, but electricity to charge it still has a carbon cost that depends on your local grid. In regions with clean grids (hydro, nuclear, renewables), the reduction is dramatic. In coal-heavy regions, the benefit is smaller but still generally positive.
Per person. The factor used here (0.000255 metric tons per passenger-mile) already accounts for average aircraft load factors. A round trip doubles the distance, so enter total miles flown both ways.
Estimate only. Results reflect your inputs and standard formulas. Double-check important decisions independently.