Scope 3: business travel and commuting

What do business travel and commuting cover?

Category 6 includes travel for work in vehicles owned or operated by others: commercial flights, trains, buses, taxis, rental cars, and employees' own cars used for work trips, often called the grey fleet. Travel in company-owned or leased vehicles the company controls is scope 1 or 2 instead. Hotel stays may be included. Category 7 covers employees' regular journeys between home and their place of work, by car, public transport or other means, and may include the energy used by employees working from home. Contractors' travel can be included where relevant. See the 15 scope 3 categories.

How are business travel and commuting emissions calculated?

• Distance-based: passenger-kilometres by mode and class, multiplied by an emission factor per passenger-kilometre. The usual choice.
• Fuel-based: litres of fuel used, for example from mileage claims with fuel receipts, multiplied by a fuel factor.
• Spend-based: travel spend multiplied by a factor per currency unit, used where distance data are missing. It is the least accurate, because prices vary far more than emissions. See the spend-based method.

Emission factors come from government sets, such as the UK's greenhouse gas conversion factors or the US EPA's emission factors hub. See emission factors.

Where does the data come from?

Travel management companies usually provide flight segments with distances and classes, rail journeys and hotel nights; expense systems capture taxis, mileage claims and bookings made outside the agency. For commuting, most companies survey a sample of employees on distance, mode and days in the office, then extrapolate to the whole workforce, adjusting for leave and part-time work. Badge or desk-booking data can refine the number of office days.

Business travel and commuting in practice: a professional services firm

A firm with 1,000 employees uses its travel agency's data, with an illustrative factor set that applies an uplift of 1.7 to flights for non-CO2 effects.

For commuting, a survey of 400 employees shows an average one-way commute of 12 km, 3 office days a week over 46 working weeks, so 3,312 km a year each, with 40% by car, 45% by rail and bus and 15% cycling or walking. That gives about 315 kg per employee, or 315 tonnes for the firm.

Long-haul business class is a quarter of the distance flown but nearly half of flight emissions before the uplift, which makes the travel policy the obvious lever. The firm discloses its factor source, that it applies the uplift, and that flight emissions would be 554 tonnes without it. See supplier-specific data.

How should flights be treated?

Use the distance of each segment, with a factor for its length band and cabin class, since premium seats take more space and carry a larger share of the aircraft's emissions. Decide whether to apply an uplift for radiative forcing, the extra warming from contrails and nitrogen oxides at altitude: the GHG Protocol does not require it, factor sets differ, and consistency and disclosure matter most. Count well-to-tank emissions of jet fuel consistently with the factor set used.

Which reporting rules require these categories?

Under IFRS S2 and the ESRS, a company reports the scope 3 categories that are significant or material to it, with the categories included disclosed. CARB's proposals for SB 253 would make business travel and employee commuting two of five mandatory scope 3 categories from 2027, with scope 3 penalties only for not filing until 2030. The SBTi requires scope 3 targets to cover significant categories. See SB 253 scope 3 from 2027.

How can companies reduce travel and commuting emissions?

Travel policies that require rail for short journeys, economy class on most flights and approval for long-haul trips; virtual meetings where they work; and, for commuting, support for public transport, cycling and electric vehicle charging, and hybrid working patterns. Because these categories are measured from good activity data, reductions show up quickly in the inventory. See setting and reporting net zero targets.

This guide is general information. It is not tax or legal advice for your situation.