Flight vs Train Emissions Calculator
Compare flying with UK national rail for the same journey. Choose distance, trip type, passengers, haul and cabin class to avoid a one-size-fits-all estimate.
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Enter a distance to compare flying and taking the train.
How it's calculated
Each mode multiplies the distance by its own per-passenger factor:
flight kg = one-way km × trip legs × passengers × selected flight factor
train kg = one-way km × trip legs × passengers × 0.03092
Flight factors vary by haul and cabin class and can include the Government's radiative-forcing uplift. Train factor: 0.03092 kg CO₂e per passenger-km. Source: UK Government GHG conversion factors 2026, business travel by air. These are UK reporting averages; real emissions vary with route, aircraft, occupancy, diversions and the rail operator.
Accuracy and limitations
- The profiles are UK Government 2026 reporting averages for UK domestic or UK-linked routes. They are estimates for other countries and carriers.
- Published flight factors include an official distance uplift. Enter the route distance once; do not add another uplift yourself.
- The rail comparison uses the 2026 UK national-rail average. International, high-speed, diesel and renewable-powered rail services can differ substantially.
Frequently asked questions
Why does flying emit so much more than the train?
Aircraft burn large amounts of fuel per passenger, especially during take-off and climb, and emissions are released at altitude. Electric or diesel trains move far more people per unit of energy, so per passenger-kilometre they emit a fraction of a flight.
Does this include the full climate impact of flying?
The radiative-forcing switch is on by default. It applies the UK Government factor that accounts for non-CO₂ effects at altitude. Turn it off to see the official result without that uplift. Neither option includes airport construction or aircraft manufacture.
Is the distance one-way or return?
Enter the one-way distance, then choose one-way or return. The calculator doubles passenger-kilometres for a return trip and also multiplies by the number of passengers.