0.205 kg CO₂e per passenger-kilometre
Short haul
Distance: < 1,500 kmTTW: 0.105 + WTT: 0.028 + RFI: 0.072
Method
How we calculate.
Our calculator gives an estimate, not a precise measurement. Actual emissions vary with aircraft type, load factor, weather and routing. What we give you is a well-founded approximation for that route, accurate enough to compare options and make informed decisions.
1 · Distance
We compute the great-circle distance between the two airports using the haversine formula on a sphere of radius 6,371 km. That's the shortest path along the Earth's surface — close to what aircraft actually fly on long-distance routes.
2 · Emission factors
We use UK DESNZ GHG Conversion Factors for economy-class passenger flights, separated into three components:
- TTW (tank-to-wake) — CO₂ from burning the jet fuel itself.
- WTT (well-to-tank) — upstream emissions from extracting, refining and transporting the fuel.
- RFI (radiative forcing index) — extra warming from contrails and high-altitude NOₓ, expressed as CO₂-equivalent.
Emissions per passenger-kilometre
All values in kg CO₂e per passenger-kilometre. Total is the sum of TTW, WTT and RFI. The short-haul figure is the average of the UK DESNZ GHG Conversion Factors for domestic flights and short-haul international flights.
0.147 kg CO₂e per passenger-kilometre
Medium haul
Distance: 1,500–4,000 kmTTW: 0.074 + WTT: 0.022 + RFI: 0.051
0.129 kg CO₂e per passenger-kilometre
Long haul
Distance: > 4,000 kmTTW: 0.064 + WTT: 0.017 + RFI: 0.048
3 · Jet fuel
Fuel use is back-calculated from the direct (TTW) CO₂ alone:
fuel_kg = TTW_CO2_kg / 3.16fuel_litres = fuel_kg / 0.80
3.16 kg of CO₂ is produced per kg of Jet-A burned; Jet-A density is ~0.80 kg/L.
4 · Airport data
We use the public OurAirports dataset, filtered to large and medium airports with scheduled service and a valid IATA code.
Comparison with other transport
The calculator also compares the flight's emissions per passenger-kilometre with typical ground alternatives. Figures come from the UK DESNZ GHG Conversion Factors for an average vehicle. All values in kg CO₂e per passenger-kilometre.
0.105 kg CO₂e per passenger-kilometre
Petrol car
Use phase: 0.163 + Upstream: 0.046 = 0.209 per vehicle ÷ 2 passengers = 0.105
0.021 kg CO₂e per passenger-kilometre
Battery electric car
Use phase: 0.036 + Upstream: 0.006 = 0.042 per vehicle ÷ 2 passengers = 0.021
0.005 kg CO₂e per passenger-kilometre
Electric train
National rail average
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