ICAO Carbon Emissions Calculator

ICAO's ICEC distinguishes passenger and freighter calculations and links both a web portal and an API. The passenger methodology, version 13.1 dated August 2024, describes choosing origin/destination and cabin, then estimating kg of CO2 per passenger from scheduled aircraft mixes, great-circle distance, load factors and cargo allocation. Connections with different flight numbers are calculated as separate legs and added; a same-flight-number through service can be represented by its multi-stop schedule, and codeshares should be counted once. These are industry-average estimates rather than measurements of a particular flight. ICAO's FAQ excludes radiative-forcing and other non-CO2 multipliers, so its result is not directly equivalent to a calculator reporting a wider aviation climate footprint. The product page describes a newer 2026 four-cabin offering; the linked guide's detailed steps retain their stated 2024 version scope.