Flight: DEFRA 🇬🇧

Calculate passenger flight emissions with the UK government's DEFRA Conversion Factors, pinned to a factor year or using the latest supported one.

The UK Department for Environment, Food and Rural Affairs (DEFRA) provides a standardised way to evaluate the emissions of passenger air travel. Its methodology takes into account the aircraft's fuel consumption, flight distance, aircraft type and the indirect effects of high-altitude emissions.

Sample requestsCopy Anchor Link

Send a quote while the traveller is still choosing a flight, then repeat the call with audit set to true once the booking is final. The body is otherwise identical.

{
  "expand": ["items"],
  "items": [{
    "audit": false,
    "type": "flight",
    "methodology": "DEFRA",
    "external_reference": "test_4",
    "number_of_travelers": 2,
    "origin": "LON",
    "destination": "LAX",
    "booking_class": "first",
    "aircraft_type": "737",
    "radiative_forcing_index": true,
    "energy_scope": "wtw",
    "methodology_version": "2024"
  }]
}

DefaultsCopy Anchor Link

When a field is missing, SQUAKE fills it in before calculating.

How it's calculatedCopy Anchor Link

• An 8% uplift is applied to the great-circle distance (GCD) to account for indirect paths, delays and similar factors.
• If you send both distance_in_km and origin/destination, distance_in_km takes precedence.

Request fieldsCopy Anchor Link

Aircraft type distributionCopy Anchor Link

Sample responseCopy Anchor Link

{
  "carbon_quantity": 15273823,
  "carbon_unit": "gram",
  "items": [{
    "carbon_quantity": 15273823,
    "carbon_unit": "gram",
    "external_reference": "test_4",
    "type": "flight",
    "methodology": "DEFRA",
    "methodology_version": "2024",
    "distance": 8804.0,
    "distance_unit": "kilometer"
  }]
}

VersionsCopy Anchor Link

If methodology_version is left out, SQUAKE applies the latest supported DEFRA Conversion Factors year. Pin a year for reproducibility and audit readiness.

BibliographyCopy Anchor Link

• UK Government. Greenhouse gas emissions: research and statistics. gov.uk
• Bramwell, R., et al. (2024). Government Greenhouse Gas Conversion Factors for Company Reporting: Methodology. Methodology paper (PDF).