06
How this is calculated
DESNZ 2026
- Distance. The great-circle distance between the two airports, plus 8% for indirect routes and delays.
- Flight type. Under 500 km uses DESNZ's domestic factor (our cut-off, based on DESNZ's 434 km average UK domestic flight). Under 3,700 km is short-haul; anything longer is long-haul. DESNZ classes UK flights by region, but distance is used here so any pair of airports works.
- Cabin. Economy, or business when the estimated flight time is over your policy threshold. Flight time is estimated as distance ÷ 850 km/h + 0.55 h.
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Factors. Grams of CO₂ per passenger-km:
| Flight type | Economy | Business |
|---|
- Non-CO₂.
- Trips.
- Jetlag. Hours of time-zone difference using standard time. Daylight saving is ignored.
- Limits. Every journey is treated as one direct flight from the airport assigned to that group. Only CO₂ is counted (methane and nitrous oxide are left out), so results are slightly lower than DESNZ's own CO₂e figures. This is for comparing options, not for carbon reporting.
Source:
UK Government GHG conversion factors 2026 (DESNZ),
published 11 June 2026. Methodology paper tables 36–37, paragraphs 8.37 and 8.42.
Airports:
OurAirports (public domain).
Places, regions and time zones:
GeoNames,
licensed under CC BY 4.0.