Flight Carbon Footprint Calculator
Written by Thierno Sadou Diallo, formula verified per our methodology • Last checked on 9/10/2026
Flight emissions are calculated with distance × emission factor by haul length (230 g/km for short-haul, 178 for medium-haul, 152 for long-haul), radiative forcing included. A 500 km round trip emits about 230 kg of CO2 equivalent per passenger.
Explanation
A flight's carbon footprint depends on two main factors: the distance flown and the haul length. The emission factor per kilometer decreases with distance, because the fuel burned during takeoff and climb — the most fuel-intensive phases — is spread over more kilometers: a short-haul flight emits about 230 g of CO2 equivalent per passenger per kilometer, versus 178 g for a medium-haul and 152 g for a long-haul. These values include the radiative forcing effect: at cruising altitude, the aircraft doesn't just emit CO2, it also produces contrails and induced cirrus clouds whose warming effect adds to that of CO2 alone, roughly doubling the total climate impact. This calculator complements our trip carbon footprint calculator, which compares planes to other transport modes with a single factor without distinguishing haul length. As a benchmark, a long-haul transatlantic round trip alone represents on the order of 1.5 to 2 tonnes of CO2 equivalent per passenger, a significant share of the individual annual carbon budget compatible with the warming limitation goal. To offset these emissions through tree planting, see our trees to offset a carbon footprint calculator, bearing in mind that offsetting doesn't remove the need to reduce emissions at the source.
Example: a 500 km short-haul round trip
Inputs
Distance: 500 km. Haul length: short-haul (230 g/km). Trip: round trip.
Calculation
Total distance = 500 × 2 = 1000 km. Emissions = 1000 × 230 ÷ 1000 = 230 kg of CO2 equivalent.
Result
This 500 km round trip emits about 230 kg of CO2 equivalent per passenger.
Frequently asked questions
Why do emissions per kilometer decrease on long flights?
Takeoff and climb are the most fuel-hungry phases. On a short flight, these phases represent a large share of total consumption; on a long flight, they are spread over many more kilometers of fuel-efficient cruising, which lowers the per-kilometer average. A long-haul flight still emits much more in absolute terms, because of the distance.
What is aviation's radiative forcing?
By burning kerosene at high altitude, the aircraft emits CO2, but also water vapor and nitrogen oxides that, in the cold conditions of the upper atmosphere, form contrails and promote cirrus-type clouds. These phenomena have an additional short-term warming effect, generally estimated at about double the effect of CO2 alone, with still-significant scientific uncertainty on the exact factor.
How does this estimate compare to other calculators?
Flight calculators give results that can vary by 30 to 50% depending on whether they include radiative forcing, the load factor used, the travel class (a business class seat takes the space of two to three economy seats), and the version of the emission factors used. This estimate provides an order of magnitude consistent with ADEME data including radiative forcing, not a certified inventory.