Carbon Footprint Calculator
Estimate the yearly CO2e from your driving and flights using the U.S. EPA's 2025 emission factors.
Total per year
4.49 metric tons CO2e
- Driving
- 4,233.2 kg CO2e
- Flights
- 260.2 kg CO2e
- Total in kilograms
- 4,493.4 kg CO2e
Emission factors: U.S. EPA GHG Emission Factors Hub (January 2025) — fuel CO2 (Table 2), eGRID2023 electricity (Table 6), car and air travel (Table 10), IPCC AR5 GWPs. Counts tailpipe and flight combustion only, not fuel production or contrail effects.
Show the work
Fuel burned
gal = mi ÷ mpg
12,000 ÷ 25 = 480 gal
Driving: fuel CO2 plus CH4 and N2O
CO2e = gal × kg CO2/gal + mi × (g CH4/mi × 28 + g N2O/mi × 265) ÷ 1,000; 28 and 265 = IPCC AR5 warming factors
480 × 8.78 + 12,000 × (0.0059 × 28 + 0.0053 × 265) ÷ 1,000 = 4,233.2 kg CO2e
Flights: miles × each band's factors
CO2e = mi × (kg CO2/mi + (g CH4/mi × 28 + g N2O/mi × 265) ÷ 1,000); 28 and 265 = IPCC AR5 warming factors
2,000 × (0.129 + (0.0006 × 28 + 0.0041 × 265) ÷ 1,000) = 260.2 kg CO2e
Total in metric tons
t = (driving + flights) ÷ 1,000
(4,233.2 + 260.2) ÷ 1,000 = 4.49 metric tons CO2e
How it works
Driving: gallons × 8.78 kg CO2 (gasoline) or 10.21 (diesel), or kWh × grid rate for an EV, plus CH4 and N2O; flights: passenger-miles × EPA short/medium/long-haul factors; CO2e uses AR5 GWPs (CH4 28, N2O 265). Factors: U.S. EPA GHG Emission Factors Hub, January 2025
Questions
- How does the carbon footprint calculator work?
- Driving: gallons × 8.78 kg CO2 (gasoline) or 10.21 (diesel), or kWh × grid rate for an EV, plus CH4 and N2O; flights: passenger-miles × EPA short/medium/long-haul factors; CO2e uses AR5 GWPs (CH4 28, N2O 265). Factors: U.S. EPA GHG Emission Factors Hub, January 2025.
- What do I need to enter?
- Car, Miles driven per year, Fuel economy, Energy use, Grid CO2 rate, Short flights (under 300 mi), Medium flights (300–2,299 mi), Long flights (2,300 mi or more). Optional fields can be left blank.
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