Bus and train emission factor NZ 2026 (MfE, kg CO2e per passenger-km)

The 2026 Ministry for the Environment emission factor for travel by bus (average bus) is 0.1449 kg CO2e per passenger-km. Metropolitan rail averages 0.02704 kg per passenger-km and an electric bus 0.01757 kg. These are from the 2026 guide, the only edition we hold for this factor, so there is no change from last year to show.

Updated 19 October 2026 by the Carbon Recycling team. Figures are from the Ministry for the Environment's 2026 emission factors (version 2, CC BY 4.0), checked against the published file on 19 October 2026.

Work out your bus travel emissions

Passenger-km in a year

= 724.6 kg CO2e in 2026 (Scope 3 (business travel or commuting))

Each passenger-km × 0.1449 kg CO2e, the Ministry for the Environment's 2026 figure (Average Bus).

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Bus, train and ferry emission factors in the 2026 guide

Factor (as the Ministry names it)	Unit	kg CO2e	CO2	CH4	N2O
Average BusPublic Transport Passenger Travel › Bus	per passenger-km	0.1449	0.1427	0.0002781	0.001993
National Average for BusPublic Transport Passenger Travel › Bus	per passenger-km	0.1553	0.153	0.000125	0.002125
Diesel BusPublic Transport Passenger Travel › Bus	per passenger-km	0.1685	0.1659	0.000249	0.002357
Electric BusPublic Transport Passenger Travel › Bus	per passenger-km	0.01757	0.01711	0.0004348	0.00002818
Hydrogen BusPublic Transport Passenger Travel › Bus	per passenger-km	0.03327	0.03241	0.0008088	0.00005261
Metropolitan AveragePublic Transport Passenger Travel › Rail	per passenger-km	0.02704	0.02638	0.0005199	0.0001356
Metropolitan ElectricPublic Transport Passenger Travel › Rail	per passenger-km	0.02043	0.01987	0.000523	0.00003666
Metropolitan DieselPublic Transport Passenger Travel › Rail	per passenger-km	0.2739	0.2697	0.0004049	0.003832
Ferry AveragePublic Transport Passenger Travel › Ferry	per passenger-km	0.6617	0.6515	0.0009781	0.009257

CO2, CH4 and N2O are each gas's share of the total, in kg CO2e; a dash means the guide gives no figure for that gas. Every figure is from the 2026 guide; it is the only edition we hold, so there is no year-on-year column.

The Ministry's notes on these figures

National Average for Bus: Factors unchanged from previous edition.

Worked example

Take staff travelling 5,000 km by bus for work in a year. 5,000 passenger-km × 0.1449 kg CO2e = 724.6 kg CO2e, reported as Scope 3 (business travel or commuting).

How to use it

Multiply the distance each person travelled by the factor. Use the bus type where you know it, since electric buses are far lower; otherwise use the average bus.

The guide lists two bus averages. The 'National Average for Bus' row is marked as unchanged from the previous edition; whichever you pick, use the same one every year.

Most metropolitan trains in Auckland and Wellington are electric, which is why the rail average is so low. Travel for work is Scope 3 business travel; daily commutes are Scope 3 employee commuting.

Which rules apply in New Zealand

The Ministry's guide is voluntary guidance for organisations measuring their greenhouse gas emissions, and follows the GHG Protocol and ISO 14064-1. Climate reporting entities under New Zealand's climate-related disclosures regime report under the External Reporting Board's Aotearoa New Zealand Climate Standards, and can use these factors for their Scope 1, 2 and 3 figures. Businesses of any size answering a customer's or a bank's request for emissions data can use them in the same way. Cite the guide and its year next to every figure.

UK companies with sites or staff in New Zealand should use these factors for that activity and the UK government factors for UK activity. In Carbon Recycling, set a site's country to New Zealand and its electricity is reported with the Ministry's factor. See reporting overseas sites for how the rest fits together.

Where to find your own figure

Expense claims, travel card statements or a staff commuting survey give distances.

Related emission factors

Working from home (New Zealand): 0.8161 kg CO2e per employee day
Taxi (New Zealand): 0.159 kg CO2e per km
Domestic flights (New Zealand): 0.1159 kg CO2e per passenger-km
All New Zealand emission factors
New Zealand grid electricity (Ember's estimate, every year since 2000)
UK emission factors and other countries

Source: Ministry for the Environment. 2026. Measuring emissions: A guide for organisations: 2026 emission factors (version 2). Crown copyright, licensed under CC BY 4.0. Carbon Recycling is not affiliated with or endorsed by the Ministry; the sums on this page are ours.

Frequently asked questions

Which bus factor should I use?

The bus type if you know it; otherwise the average bus. Say which you used.

Who publishes these factors?

The Ministry for the Environment, in Measuring emissions: A guide for organisations, with a new set of factors each year. The Ministry is now part of the Ministry for Cities, Environment, Regions and Transport. The factors are Crown copyright, licensed under CC BY 4.0.

We are a UK company with staff or a site in New Zealand. Which factor do we use?

Use the New Zealand factor for activity in New Zealand: its electricity, fuel bought there and travel within the country. Keep using the UK government factors for UK activity, and say in your report which set you used where.

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