Flight methodology
DEFRA
UK Government conversion factors
Distance-based factors from the UK Government's greenhouse gas conversion factors for company reporting. The factors are now published by the Department for Energy Security and Net Zero (DESNZ); SQUAKE keeps the name DEFRA.
- Publisher
- UK Government (DESNZ)
- Best for
- UK-based company reporting
- Result
- One total per trip, for all travellers
- Energy scope
- WTW by default, TTW optional
- Non-CO₂ effects
- Included by default, can be switched off
- Factor year
- Selectable; latest supported year by default
How it works
- Emissions use the great-circle distance between the airports, or the actual distance where known. The UK factors already include an 8% uplift for indirect flight paths and delays, so SQUAKE does not add it again. The distance SQUAKE reports does include the 8%.
- The factor depends on the flight type (domestic, short haul under 3,700 km, long haul or international) and the cabin class.
- SQUAKE uses the aircraft type only when at least one airport is in the UK.
- Non-CO₂ effects use the UK Government's multiplier (1.7 in recent factor sets).
Trip details used
When a detail is missing, SQUAKE uses the default.
| Detail | Default | Notes |
|---|---|---|
| Origin and destination airports | Required | Trips with connections are calculated leg by leg. |
| Actual distance | Calculated from the airports | Replaces the airport-based distance. |
| Cabin class | Average | |
| Number of travellers | 1 | |
| Aircraft type | None | Used when at least one airport is in the UK. |
| Sustainable aviation fuel | None | A SQUAKE adjustment outside the official UK factors. |
What is included
Included
- CO₂, methane and nitrous oxide from burning the fuel
- Producing and delivering the fuel (on by default)
- Non-CO₂ effects through the UK multiplier (on by default)
Not included
- Aircraft manufacture and airport infrastructure
Limitations
- Factors are averages for each flight type and cabin, not for a specific airline or aircraft.
- Results with and without non-CO₂ effects are not comparable.
Sources
- UK Government: conversion factors for company reportinggov.uk
Every annual factor set, with its methodology paper.
- UK Department for Transport: journey emissions methodologygov.uk
Confirms that the 8% uplift is built into the UK flight factors.