Passenger Vehicle Emission Factors

68 passenger vehicle emission factors held in the GreenCalculus MasterBrain, drawn from UK DEFRA/DESNZ 2026. Values are read live from the data layer on every page build, so nothing here is re-typed and nothing can drift from the figures the calculators use. They span 2 units of measurement — 34 of them in kg CO2e per km — which is why the spread below is reported per unit and never blended.

Where these factors are used

Business Travel by Car Emissions and Mobile Combustion set out how factors in this group are applied, and Business Travel Emissions Calculator and Scope 3 Cat 7 Employee Commuting & Work-From-Home Calculator draw on them directly. Each value below names the upstream source it came from.

What this group contains

Figures are computed per unit and never blended: a median across different units would be arithmetically valid and physically meaningless.

What has changed

Change history is reconstructed from every released edition of the data layer, v2025.13 to v2026.107. A factor absent from this table has held the same value throughout. A change shown as a dash moved off zero, where a percentage has no meaning. 35 further revalued factors are not listed here.

Sources, citation & machine access

Cite the upstream publisher for the values themselves. The reference below credits this compilation and, more usefully, pins the edition you read.

Say, Jeremiah (2026). Passenger Vehicle Emission Factors (MasterBrain v2026.110). GreenCalculus. https://greencalculus.com/factors/passenger-vehicle-emission-factors/

Cite this factor group

Values change between editions. Quoting the MasterBrain version is what lets a reader resolve the exact number you used — see the change record above for factors in this group that have moved.

For a reference manager — BibTeX, then RIS:

@misc{greencalculus_passenger_vehicles_2026,
  author       = {Say, Jeremiah},
  title        = {Passenger Vehicle Emission Factors},
  year         = {2026},
  howpublished = {GreenCalculus},
  note         = {MasterBrain v2026.110},
  url          = {https://greencalculus.com/factors/passenger-vehicle-emission-factors/}
}

TY  - DATA
AU  - Say, Jeremiah
TI  - Passenger Vehicle Emission Factors
PY  - 2026
PB  - GreenCalculus
ET  - MasterBrain v2026.110
UR  - https://greencalculus.com/factors/passenger-vehicle-emission-factors/
ER  - 

Every factor on this page is readable from the open endpoint. No key, no signup:

https://greencalculus.com/wp-json/greencalculus/v1/factors/passenger_vehicles

curl -s "https://greencalculus.com/wp-json/greencalculus/v1/factors/passenger_vehicles?limit=500"

import requests
rows = requests.get("https://greencalculus.com/wp-json/greencalculus/v1/factors/passenger_vehicles", params={"limit": 500}).json()["factors"]
print(len(rows), "factors in passenger_vehicles")

Or the same rows as a spreadsheet — every factor with its source, the edition it last changed in, and its own link:

https://greencalculus.com/wp-json/greencalculus/v1/factors-export?page=passenger-vehicle-emission-factors

Download this table as CSV

Both responses carry an X-GC-Version header, so a consumer can detect a new edition without diffing the payload. The CSV filename carries the edition too, so two downloads months apart do not collide.

All factors

Last changed names the data-layer edition in which a factor last took a new value, reconstructed from every released edition since v2025.13. A dash means the value has not moved since tracking began — which is the answer to "is the figure I used last year still current?".

Common questions