Method: Passenger travel activity is calculated as: Passenger-km = Distance per Trip × Number of Trips × Number of Travelers Total greenhouse gas emissions are: CO₂e = Passenger-km × Emission Factor For example: 1,000 km × 2 trips × 3 travelers = 6,000 passenger-km At 150 g CO₂e/passenger-km: 6,000 × 150 = 900,000 g CO₂e = 900 kg CO₂e The calculator converts miles to kilometres automatically. Emission factors should reflect the travel mode and reporting methodology being used. Air travel factors can vary by flight distance, cabin class, aircraft type, load factor and whether non-CO₂ aviation effects or radiative forcing adjustments are included. Car and taxi factors may be expressed per vehicle-kilometre rather than passenger-kilometre in some datasets. Do not use a vehicle-kilometre factor in this calculator unless it has first been converted to a passenger-kilometre basis using an appropriate occupancy assumption. Rail and bus factors also vary by energy source, occupancy and geography. This calculator estimates travel-related emissions only. Accommodation, meals, airports, vehicle manufacture and other business-travel impacts are excluded unless already incorporated in the factor entered.