How to calculate Scope 3.6 emissions from business travel

How to calculate Scope 3.6 emissions from business travel

Scope 3.6 emissions refer to greenhouse gas (GHG) emissions from business travel under the GHG Protocol. To calculate them, companies need to gather actual travel activity data, apply the right emission factors, and convert it into CO₂ equivalents (CO₂e). This guide walks through the process step-by-step to help you move from assumptions to actuals.

What is Scope 3.6 in the GHG Protocol?

Scope 3.6 includes indirect emissions from business travel activities not owned or controlled by the company. That means flights, trains, hotels, taxis, ride-hailing apps, and other forms of employee travel booked through third parties.

Business travel is one of 15 Scope 3 categories defined by the GHG Protocol and is especially relevant for companies with global operations or frequent employee travel.

Example: If your employee flies from Berlin to New York for a client meeting, the emissions from that flight fall under Scope 3.6.

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A quick rule of thumb: If it’s travel for work, not to work, and it's not your own vehicle, it’s probably Scope 3.6.

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Why Scope 3.6 matters now

• Regulatory pressure: Frameworks like CSRD, SECR, and others increasingly require Scope 3 reporting.
• Budget implications: Travel is a cost driver, and so are CO₂ reductions.
• Accuracy matters: Investors, clients, and stakeholders now want actuals, not estimates.
• Cross-functional pressure: Travel, sustainability, and finance are converging fast.

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Step-by-step: How to calculate Scope 3.6 emissions

Step 1: Collect your business travel data

• Pull data from your TMC, expense platform, or internal booking tools
• Include: date, mode of transport, distance, class of travel, destination

Step 2: Clean and categorise

• Split by transport type: air, rail, car, hotel, etc.
• Identify any missing fields (e.g. cabin class for flights)

Step 3: Match with emission factors

• Use reputable sources like DEFRA, ICAO, or EEIO databases
• For hotels: use Green Stay or industry-average kg CO₂e/night factors

Step 4: Convert to CO₂e

• Multiply activity data by emission factor
• Convert any CH₄ or N₂O into CO₂ equivalents

Step 5: Aggregate and report

• Group by category, department, geography or supplier
• Report as Scope 3.6 in your sustainability or ESG disclosure

Want to skip steps 1 to 5? Tools like SQUAKE can do it automatically.

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Common mistakes to avoid

• Using average distances instead of actual routes
• Ignoring class of travel (economy vs business = huge delta)
• Reporting flights but not hotels
• Overestimating hotel emissions with default values
• Forgetting about trips booked outside your TMC

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Tools and templates for Scope 3.6 reporting

Here are some tools that can help:

• SQUAKE: Automates calculations, matching, and aggregation
• DEFRA: UK government emission factor database
• ICAO calculator: Standard aviation emission estimation
• HRS Green Stay: Hotel-specific CO₂ data
• Excel template: Start simple with your own tracker

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FAQ

Q: What’s the difference between Scope 3.4 and Scope 3.6?
A: Scope 3.4 covers upstream transport of goods. Scope 3.6 covers employee travel.

Q: Is hotel stay included in Scope 3.6?
A: Yes, as long as it’s part of a business trip.

Q: What if I don’t have exact data?
A: Use best-available estimates but flag assumptions. Improve data quality over time.

Q: How do I calculate emissions from different modes of business travel?

A: Calculating emissions varies by transportation mode:​

• Air Travel: Multiply the flight distance by an emission factor required by your methodology of choice (e.g., aircraft type and class, distance, etc).
• Rail Travel: Use distance traveled and detour factor and apply the appropriate emission factor for the train type.​
• Car Travel: Determine the distance driven and detour factor and multiply by the vehicle's emission factor, considering fuel type and efficiency.​

For accurate emission factors, refer to resources like the UK Government's GHG Conversion Factors.​

Turn your travel data into action

Calculating Scope 3.6 emissions isn’t just about compliance. It’s about cost, visibility, and control. Companies that track actuals not only meet reporting needs also uncover opportunities to optimise spend and reduce their footprint.

Ready to get started? Book a walkthrough of SQUAKE’s Scope 3.6 solution.

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