Greenhouse Gas Emissions Calculator
Estimate your annual greenhouse gas (GHG) emissions in kilograms of CO₂ equivalent (kg CO₂e) from common sources including electricity consumption, natural gas usage, vehicle travel, and air travel.
⚡ Electricity
🔥 Natural Gas
🚗 Vehicle Travel
✈️ Air Travel
Formulas Used
Electricity Emissions (kg CO₂e):
= Monthly kWh × 12 × Grid Emission Factor (kg CO₂e/kWh)
Natural Gas Emissions (kg CO₂e):
= Monthly Therms × 12 × 5.302 kg CO₂e/therm
(EPA factor: 53.02 kg CO₂e per million BTU; 1 therm = 100,000 BTU)
Vehicle Emissions (kg CO₂e):
= (Annual Miles ÷ MPG) × Fuel Emission Factor (kg CO₂e/gallon)
Gasoline: 8.887 kg CO₂e/gal | Diesel: 10.180 kg CO₂e/gal | E85: 5.500 kg CO₂e/gal
Flight Emissions (kg CO₂e):
= Number of Round Trips × Round-Trip Distance (km) × 0.255 kg CO₂e/km × Class Multiplier
Short-haul: 1,600 km RT | Medium-haul: 5,000 km RT | Long-haul: 16,000 km RT
Class multipliers: Economy ×1.0 | Premium Economy ×1.5 | Business ×2.0 | First ×2.9
(Includes ICAO radiative forcing multiplier of 1.9 for high-altitude effects)
Total Emissions:
= Electricity + Natural Gas + Vehicle + Flights (kg CO₂e/year)
Tree Offset:
= Total Emissions ÷ 21.77 kg CO₂/tree/year
Assumptions & References
- Electricity emission factors sourced from the US EPA eGRID 2022 database by grid subregion.
- Natural gas emission factor of 5.302 kg CO₂e/therm from EPA Emission Factors for Greenhouse Gas Inventories (2023), including CO₂, CH₄, and N₂O.
- Gasoline emission factor of 8.887 kg CO₂e/gallon and diesel 10.180 kg CO₂e/gallon from EPA (2023). E85 factor accounts for biogenic carbon credit.
- Flight emission factors based on ICAO Carbon Emissions Calculator methodology with a radiative forcing index (RFI) multiplier of 1.9 applied to account for non-CO₂ warming effects at altitude (contrails, NOx, etc.).
- Average round-trip distances: short-haul ~1,600 km, medium-haul ~5,000 km, long-haul ~16,000 km.
- Business and first class multipliers reflect greater seat area and per-passenger fuel share per DEFRA/BEIS 2023 guidance.
- US average per-capita emissions of 16 metric tonnes CO₂e/year from EPA (2022).
- Tree sequestration rate of 21.77 kg CO₂/tree/year from US Forest Service estimates for average US tree species.
- This calculator estimates direct and indirect (Scope 2) emissions; supply chain (Scope 3) emissions beyond those listed are not included.
- References: EPA GHG Equivalencies Calculator; ICAO Carbon Offset and Reduction Scheme; DEFRA/BEIS UK Government GHG Conversion Factors 2023; US Forest Service Carbon Online Estimator.