How to Calculate Carbon Emissions from your Local Bus Trip

Written by Ellen West on 14 January, 2021

You may wonder how much carbon is emitted by travelling on your local bus. Per passenger, buses emit far less carbon than cars, but what exactly is their carbon impact? To calculate the carbon emissions from your local trip, we refer to the conversion factors provided by the UK Government.

First, you need to find the route distance in question. Buses often travel on a similar route to the same route taken by car/taxi. However, sometimes the route deviates. Google Maps will often show you the actual bus route, so you can use that to estimate distance. For more accurate distances, you can also refer to your travel provider. Once you have the distance, you simply need to multiply the distance in kilometres (km) by the conversion factors displayed below.


CO2e per pkm

CO2 per pkm

CH4 per pkm

N2O per pkm

Local Bus (not London)





Local London Bus





Average Local Bus





Note: Units are in per passenger-kilometre (pkm). For example, 2 people travelling 100km would be 200 passenger-kilometres.

As you can see, the factors differ depending on whether you travel in or out of London. They are also dependant on the type of greenhouse gas. Best-practice is to calculate CO2e, as it best represents total emissions.

Worked example: 2 people travel 5 miles by local bus in Leeds. 5 miles is 8 kilometres. Since we measure in passenger-kilometres, we need to multiply the kilometres by the number of passengers, to get 16 passenger-kilometres. Finally, we multiply this by the number in the table (0.1195) to get 1.9 kg of CO2e.

For more examples, here are some carbon emissions calculations on some UK routes:

  • The carbon emissions of Euston to Elephant and Castle by local London bus is 0.41 kg of CO2e (5.3 km travelled per passenger).
  • The carbon emissions of Newcastle City Centre (Haymarket) to Newcastle International Airport by local bus (not London) is 1.27 kg of CO2e (10.6 km travelled per passenger).
  • The carbon emissions of Glastonbury town to Bristol City Centre by local bus is 5.40 kg of CO2e (45.2 km travelled per passenger).

To power this article and our calculation, we have relied upon expert research by the UK Government's Department for Business, Energy & Industrial Strategy, and the Department for Environment, Food & Rural Affairs. The approximate distances have been sourced using Google Maps.


You can find more conversion factors here. For detailed explanations, stay tuned for more data-driven insights from the Thrust Carbon team. Let’s make travel effortlessly green together.

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