Carbon Footprint Calculator

1. Transportation: enter your annual car mileage and your vehicle's MPG. If you drive very little or use an electric car, enter 0 miles. The US average is about 14,000 miles per year.
2. Flights: count round trips separately. A short-haul flight is typically under 3 hours (for example, New York to Chicago). A long-haul flight is 3 or more hours (New York to London, Los Angeles to Tokyo). Enter round trips, not one-way legs.
3. Electricity: find your monthly kWh usage on your electricity bill. The US household average is about 900 kWh per month. Larger homes and homes in hot or cold climates use more.
4. Home heating: select your primary heating fuel. Natural gas and electric heat pump households have lower emissions than heating oil or propane.

The calculator focuses on the four largest sources of household emissions. It does not include food, manufactured goods, or services, which add another 4 to 6 tons to the average US footprint.

Driving emissions:
  CO2 (tons) = (Miles ÷ MPG) × 8.89 kg/gallon ÷ 1,000

Flight emissions (round trip, economy class):
  Short haul: 0.255 metric tons per flight
  Long haul:  1.5 metric tons per flight

Electricity emissions:
  CO2 (tons) = kWh/month × 12 × 0.386 kg/kWh ÷ 1,000
  (US average grid emission factor: 0.386 kg CO2/kWh)

Home heating (annual average US home):
  Natural gas:  ~2.0 metric tons CO2
  Electric:     ~0.5 metric tons CO2 (additional above electricity)
  Heating oil:  ~3.2 metric tons CO2

Emission factors source: US EPA, International Energy Agency (IEA), and ICAO carbon calculator methodology (2024).

Tree offset estimate: a mature tree absorbs roughly 48 to 60 kg (about 0.05 to 0.06 metric tons) of CO2 per year. Offsetting 1 metric ton of CO2 requires approximately 17 trees growing for one year. Planting trees is one strategy, but reducing emissions at the source is significantly more effective per dollar.