National rail travel: carbon footprint per passenger-km
Live factor value
0.03092 kgCO2e per passenger-km
Source: UK DESNZ greenhouse-gas conversion factors, 2026 (revision 2). Factor set desnz-2026-r2.
Train travel is one of the lowest-carbon ways to cover distance in the UK: the official DESNZ 2026 national rail factor, shown below per passenger-kilometre, is roughly a fifth of the average car's per-km figure. The factor averages across the whole network — electric and diesel services alike.
Because the factor is per passenger-km, your footprint for a journey is simply the rail distance multiplied by the factor — no assumptions about the specific train. As the network electrifies and the grid decarbonises, this factor falls year on year.
Worked example
London to Manchester by train, one way (~335 km): 335 × 0.03092 = 10.4 kgCO2e.
Measure your own with the free travel calculator.
Frequently asked questions
- What is the carbon footprint of UK train travel per km?
- 0.03092 kgCO2e per passenger-km in the DESNZ 2026 conversion factors — around five times lower than driving the same distance alone in an average car.
- Is the train always lower-carbon than driving?
- Per passenger, almost always in the UK. A car with several occupants narrows the gap, but a lone driver emits several times more per km than a rail passenger on the official averages.