What is Scope 3 Category 6?

Category 6 of the GHG Protocol Scope 3 standard covers emissions from employee business travel in vehicles not owned or operated by the company — flights, trains, rental cars, taxis, and associated hotel stays. It is one of the 15 Scope 3 categories.

Where do the emission factors come from?

The factors are kg CO2e per passenger-km (or per room-night) drawn from the UK DEFRA/BEIS 2024 greenhouse gas conversion factors. Flight factors include a radiative-forcing uplift to capture non-CO2 high-altitude warming effects.

Why does business-class flying emit more?

Premium cabins allocate more aircraft floor space per passenger, so each traveller carries a larger share of the flight's total emissions. DEFRA applies multipliers, making long-haul first class roughly four times the economy factor per km.

Should I use distance or spend?

Distance-based calculation (passenger-km) is more accurate and is preferred under the GHG Protocol. Spend-based factors are a fallback when you only have expense data. This tool uses the distance method.

Does this cover hotel stays?

Yes. Accommodation is part of Category 6 business travel. The tool applies a per-room-night factor for a UK-average hotel; for other countries the factor varies, so adjust if you have location-specific data.

What is the Scope 3 Business Travel Emissions Calculator?

Enter trips by mode (flight cabin class, rail, car type, taxi, hotel nights) and quantities to compute total Scope 3 Category 6 business travel CO2e using DEFRA 2024 emission factors. Produces a per-line breakdown for your GHG inventory and CSRD travel disclosure. It runs free in your browser on Gera Tools, with nothing uploaded.

Scope 3 Business Travel Emissions Calculator

Name: Scope 3 Business Travel Emissions Calculator
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

This tool calculates the greenhouse-gas emissions from business travel — GHG Protocol Scope 3, Category 6 — by multiplying each trip by its emission factor. Build an itinerary of flights, rail, road journeys, taxis, and hotel nights, and get the total in kg and tonnes CO2e for your carbon inventory.

How it works

Each travel mode has an emission factor measured in kilograms of CO2e per unit of activity:

Flights, rail, cars and taxis use kg CO2e per passenger-km.
Hotels use kg CO2e per room-night.

The calculation for each line is simply:

emissions (kg CO2e) = quantity × emission factor

The lines are then summed to give the Category 6 total. For example, a 1,500 km short-haul economy flight at a factor of 0.15102 kg/passenger-km produces 1,500 × 0.15102 ≈ 227 kg CO2e.

Why cabin class matters

DEFRA publishes separate factors per cabin because premium seats occupy more space and therefore carry a greater share of the aircraft’s fuel burn:

Mode	kg CO2e / passenger-km
Long-haul economy	0.19562
Long-haul business	0.56730
Long-haul first	0.78249

Flight factors already include a radiative-forcing multiplier for the extra warming caused by emissions at altitude.

Radiative forcing explained

Flights produce CO2 at altitude, but they also produce contrails and nitrogen oxide emissions that have additional warming effects not captured by the CO2 figure alone. The radiative-forcing (RF) uplift in DEFRA’s flight factors accounts for this extra warming. It is why a long-haul economy factor of roughly 0.20 kg CO2e/passenger-km is higher than the equivalent surface-transport factor for the same distance — the total warming effect is greater than the raw fuel burn would suggest. Some organisations report both the market-based (CO2 only) and the RF-adjusted figure; the GHG Protocol recommends disclosing the RF uplift separately rather than blending it silently.

What to enter for distance

For flights, use the great-circle distance between airports. Many airline booking systems display this on your itinerary, or you can look it up. For rail and car journeys, use the route distance in km. The tool works in passenger-km, not vehicle-km, so each passenger on a shared journey should enter the full route distance — the emission factor already accounts for average occupancy at the mode level.

Using the output for reporting

Under the Corporate Sustainability Reporting Directive (CSRD) and the GHG Protocol, Category 6 should be reported in tonnes CO2e alongside your Scope 1 and 2 figures. The per-line breakdown this tool produces makes it straightforward to identify the highest-emitting activities — typically long-haul business-class flights — and to set reduction targets by mode or by policy (for example, replacing short-haul flights under 500 km with rail alternatives).

Document the emission factor source and version in your report. These factors update annually, so a 2024 inventory should reference DEFRA/BEIS 2024 specifically rather than just “DEFRA factors.” If your auditor requests a methodology note, the factor source plus “distance-based method per GHG Protocol Scope 3” is a concise and accurate description.

Notes

Factors reflect the UK DEFRA/BEIS 2024 conversion set. If your company reports under CSRD or the GHG Protocol, document the factor source and version alongside the totals. For non-UK hotel stays and electricity-grid-dependent EV charging, substitute country-specific factors where you have them. All calculation runs locally in your browser.