How we calculate travel emissions

The SCIF travel carbon calculator estimates greenhouse gas emissions from travel using official emissions factors published by the UK Department for Environment, Food & Rural Affairs (DEFRA). 

The calculator multiplies the input travel distance by the relevant DEFRA emissions factor for mode of travel and class of travel, expressed in kilograms of CO₂ equivalent (kgCO₂e) per passenger-kilometre (or per vehicle-kilometre for private transport). 

All DEFRA factors are kept up to date in line with the most recent annual release to ensure accuracy and consistency with UK government reporting standards.

Mode of Transport	kgCO₂e/km
Hybrid Car	0.12825
Electric Car	0.04047
Petrol Car	0.16272
Diesel Car	0.17304
Bus	0.10385
Train (National Rail)	0.03546
Train International	0.00446
UK flights only (origin or destination in the UK)
Flight (Short-haul) Economy	0.12576
Flight (Short-haul) Business	0.18863
Flight (Long-haul) Economy	0.11704
Flight (Long-haul) Premium Economy	0.18726
Flight (Long-haul) Business	0.33940

 

The cut-off for short-haul and long-haul is 3,700 km, anything beyond that distance is considered long-haul, this however only applies to flights originating in the UK or flying to the UK.

For flights not connected to the UK the following emissions factors should be used without any differentiation between short-haul and long-haul.

 

Mode of Transport	kgCO₂e/km
Economy	0.10916
Premium Economy	0.17465
Business	0.31656

 

Values in other travel carbon calculators may differ slightly. We have applied due diligence to ensure SCIF travel carbon calculator estimates are as accurate and balanced as possible.