# How does a bus operator calculate emissions per passenger-km?

Canonical: https://senseible.earth/answers/bus-operator-emissions-per-passenger-km

Multiply the diesel bought for the fleet by 2.68 kg CO2 per litre and divide by passenger-km: passengers carried times km per trip, from tickets or seat logs. Occupancy decides the result, so report per bus-km as well.

## Data needed

- Diesel from fuel invoices or fuel cards.
- Passengers per trip, from tickets or headcounts.
- Trip distance from the route schedule or GPS.

## Two figures

Per bus-km shows fuel efficiency; per passenger-km shows how well buses are filled. Clients and schools want the second.

## For clients

A company hiring your buses for staff reports them in Scope 3, Category 7. A per passenger-km figure from real diesel is better than a default factor.

## Worked example: bus fleet (one month, illustrative inputs)

- Diesel: 30,000 litres x 2.68 = 80,400 kg CO2
- Passenger-km: 1,000,000
- Per passenger-km: 80,400 / 1,000,000 = 0.0804 kg CO2

Inputs are illustrative; use fuel records and ticket counts.

## What Senseible does here

Senseible reads fuel invoices and fuel card statements (diesel 2.68 and CNG 2.69 kg CO2, IPCC 2006 defaults) into a fingerprinted Scope 1 record. Hired transport goes to the Scope 3 evidence trail, and distance or tonne-km estimates are labelled as estimates.

- [Student commuting in Scope 3](https://senseible.earth/answers/student-commuting-scope-3-school)
- [Business car travel: which scope?](https://senseible.earth/answers/business-car-travel-which-scope)

Sources: [IPCC 2006 Guidelines, Volume 2 Energy (fuel defaults)](https://www.ipcc-nggip.iges.or.jp/public/2006gl/vol2.html), [GHG Protocol Corporate Standard](https://ghgprotocol.org/corporate-standard), [GLEC Framework for logistics emissions (Smart Freight Centre)](https://www.smartfreightcentre.org/en/our-programs/emissions-accounting/global-logistics-emissions-council/)

Last reviewed 2026-10-21.