How to Report Business Travel Emissions for CSRD (Flights, Hotels, Trains)

Business travel is one of the most common — and most consistently underestimated — sources of Scope 3 emissions for small and growing businesses (SMEs). Whether your team travels by plane, train, or car, those journeys contribute to your company’s overall carbon footprint, and customers or banks asking for Scope 3 data will expect them to be included.

The good news is that you do not need complex software or perfect data to comply. The European Sustainability Reporting Standards (ESRS E1) and VSME Standard (EFRAG 2024) both allow well-documented estimates when travel records are incomplete. This guide walks through what counts, how to calculate it, and how to disclose it clearly.

For general guidance on handling gaps in your sustainability data, see How to Estimate Missing Data for CSRD Reporting.

1. What Counts as Business Travel Under CSRD?

Business travel covers all transport and accommodation used by employees for work-related purposes, excluding daily commuting. It falls under Scope 3, Category 6 of the GHG Protocol.

Activities that must be included:

Travel paid or reimbursed by the company must be included regardless of destination. Personal leisure travel does not count.

2. What Data Do You Need?

Start by identifying where travel information already exists in your business:

• Travel agency invoices — usually include route, transport mode, and class
• Expense claims and credit card reports — cover individually booked travel
• Online booking platform exports — many tools (Booking.com for Business, TravelPerk, Concur) can export annual summaries
• Mileage logs — for personal car use reimbursed by the company
• Hotel booking confirmations — for nights stayed when not booked centrally

For each trip, ideally record:

• Travel mode (flight, train, car, hotel)
• Distance in km, or spend in € if distance is not known
• Class of travel (economy, business, first) — for flights, this affects the emission factor
• Number of nights (for hotels)

If your records are incomplete, estimate using spend or typical journey distances. Estimates are acceptable as long as you document how you made them; VSME itself asks for estimated GHG emissions (VSME paragraph 30).

3. Calculating Emissions by Transport Type

Flights

Flights are typically the largest source of business travel emissions. The factors below are from the UK Government GHG Conversion Factors 2026 (DESNZ). They include a radiative forcing uplift for non-CO₂ warming effects at altitude: DESNZ applies a multiplier of 1.7 to the CO₂ component as a central estimate, and notes that the value is highly uncertain. They exclude well-to-tank (fuel supply) emissions, which DESNZ publishes separately.

These are UK factors. DESNZ defines haul by destination rather than distance: flights between the UK and Europe or North Africa count as short haul. For flights that do not touch the UK, use the “international, between non-UK airports” row. DESNZ also recommends adding 8% to great-circle distances to allow for indirect routes and circling.

Example: Two employees fly London to Amsterdam and back (about 400 km each way, short haul, economy).

• 400 km × 1.08 uplift × 2 legs × 2 passengers = 1,728 passenger km
• 1,728 × 0.126 = about 0.22 tCO₂e

Train and Rail

Train travel is significantly lower-carbon than flying and is increasingly the default for shorter routes in many EU countries.

Rail factors depend heavily on the electricity grid and the share of diesel trains, so a national factor from the country you travel in is better where one exists. The Eurostar-based international rail factor is a reasonable proxy for high-speed electric rail, but note the assumption.

Example: One employee travels Paris to Amsterdam and back by train (about 500 km each way).

• 1,000 km × 0.011 = about 11 kg CO₂e, compared with about 109 kg CO₂e for 1,000 passenger km of economy flying outside the UK (1,000 × 0.109).

Cars and Taxis

For company cars or hire cars, use the fuel type where known. For reimbursed personal vehicle use, apply the blended average if fuel type is not recorded.

The electric car factor reflects UK grid electricity. If the car is charged in another country, recalculate with that country’s grid factor.

Example: An employee drives 8,000 km per year on company business in a medium petrol car.

• 8,000 × 0.174 = about 1.39 tCO₂e

Hotels

Accommodation emissions are calculated per room per night, using a factor for the country where you stayed. DESNZ publishes country factors taken from the Cornell Hotel Sustainability Benchmarking Index, using the median across all hotel classes; it does not split them by star rating.

Factors vary widely between countries, from 4.7 for Costa Rica to 152 for the Maldives, so use the country of each stay where you can.

Example: Your team stays a combined 80 hotel nights per year in Germany.

• 80 × 13.2 = about 1.06 tCO₂e

The calculator below gives a quick breakdown across flights, rail, car and hotel nights. Check its factors against the current DESNZ set before you use the results in a disclosure:

4. What to Do with Incomplete Data

Many SMEs do not have centralised travel records, particularly for individually expensed trips. Here is a practical approach for each gap:

Document all assumptions clearly. Customers, banks and assurance providers will want to see how you estimated — a clear note is better than silence.

For more on handling data gaps across all reporting topics, see How to Estimate Missing Data for CSRD Reporting.

5. How to Disclose Travel Emissions in Your Report

Business travel sits inside Scope 3. VSME does not require Scope 3 in either module: B3 (energy and GHG emissions) requires Scope 1 and location-based Scope 2, and the Comprehensive Module says Scope 3 disclosure “can be appropriate” depending on your activities, to be presented alongside B3 if you give it (VSME paragraphs 30 and 50–53). Large in-scope companies disclose gross Scope 3 emissions under ESRS E1-6. Either way, your disclosure should cover:

1. Total business travel emissions by transport type (flights, rail, car, hotel)
2. Estimation methods used — distance-based, spend-based, or default factors
3. Emission factor sources referenced, with the year (for example UK Government GHG Conversion Factors 2026)
4. Actions taken or planned to reduce travel or shift to lower-carbon options

Example disclosure:

“In 2025, total business travel emissions were estimated at 28.5 tCO₂e, comprising 65% from flights, 25% from hotel stays, and 10% from car and rail travel. Distance-based calculations used the UK Government GHG Conversion Factors 2026 (DESNZ), with the radiative forcing uplift included for all flights. Hotel emissions used the DESNZ country factor for each stay. The company promotes train travel for journeys under 600 km and virtual meetings where client relationships allow.”

This level of disclosure is transparent and traceable, and it demonstrates that your data is methodologically sound even if it relies on estimates.

6. Reducing Business Travel Emissions

Reducing travel is often one of the fastest and most visible improvements an SME can make to its Scope 3 footprint. Practical actions:

• Establish a “train under 600 km” policy — covers most intra-European business travel routes
• Default to video conferencing for internal meetings and early-stage client calls
• Book eco-certified hotels where they are available on your routes
• Use corporate booking platforms with sustainability filters (TravelPerk, Spotnana) to automate data capture and reduce emissions at the point of booking
• Track air travel class — shifting one long-haul trip from business to economy class cuts per-passenger emissions by about two-thirds (0.339 to 0.117 kg CO₂e/passenger km in the DESNZ 2026 factors)
• Set annual targets — committing to a percentage reduction creates accountability and gives you a progress story to tell in your report

These actions can be reported under ESRS E1 (climate change mitigation actions) and, for VSME, under B2 (practices, policies and future initiatives) or C3 if you set reduction targets, and they demonstrate continuous improvement rather than just compliance.

Frequently Asked Questions

Do I need to include travel booked and paid for personally by employees?

Yes, if the travel is reimbursed by your company. All company-reimbursed transport and accommodation counts as business travel under Scope 3 Category 6. Personal travel that is not reimbursed does not count.

What if I only have travel spend, not distance data?

You can use spend-based emission factors, which are expressed in kg CO₂e per unit of currency. For example, the UK spend-based emissions multiplier for air transport services is 1.47 kg CO₂e per £ (2023, excluding VAT), or about 1.28 kg CO₂e per € at the 2023 average exchange rate. Treat this as a rough estimate: it reflects average UK supply chains and prices, not your routes or class. Disclose clearly that you used a spend-based approach and reference your factor source. Over time, improve to distance-based calculations as you collect better data.

Should I include hotel stays outside the EU?

Yes. All business travel — domestic and international — forms part of your Scope 3 inventory. There is no geographic restriction on what must be included.

Do I have to separate flights by class of travel?

If you have the data, yes. In the DESNZ 2026 factors, business-class long-haul travel carries emissions about 2.9 times higher than economy, because each seat takes up more cabin space. If booking class is not recorded, default to economy and note this assumption.

How do I handle travel by a mix of transport modes on one trip?

Calculate each leg separately and sum them. For example, a trip involving a train from Amsterdam to Brussels, then a flight from Brussels to Madrid, would be calculated as: train leg (international rail factor) + flight leg (international flight between non-UK airports, economy).

Sources

• UK Government GHG Conversion Factors for Company Reporting 2026 (DESNZ), flat-format file, sheet “Factors by Category” (Business travel – air rows 4410–4506; Business travel – land rows 5205–5473; Hotel stay rows 7395–7449): https://assets.publishing.service.gov.uk/media/6a6c9748862aaf18d9c62ac9/ghg-conversion-factors-2026-flat-format-revised.xlsx
• 2026 GHG Conversion Factors Methodology Paper (DESNZ): radiative forcing multiplier of 1.7 (paragraphs 8.39–8.44), 8% great-circle uplift (8.36–8.38), short- and long-haul definitions (8.8–8.9), hotel stay factors (11.1–11.7): https://assets.publishing.service.gov.uk/media/6a2940543b15d05a7ce3202e/2026-GHG-conversion-factors-methodology-report.pdf
• Spend-based emissions multipliers, 1997 to 2023 (Defra, published 30 June 2026), sheet “SIC_multipliers_2023”, SIC 51 air transport services: https://assets.publishing.service.gov.uk/media/6a3ce5fa33bc5beefd3c4983/spend_based_emissions_multipliers_1997_to_2023.ods
• ECB euro reference exchange rate, annual average 2023: €1 = £0.86979: https://data-api.ecb.europa.eu/service/data/EXR/A.GBP.EUR.SP00.A
• EFRAG VSME Standard (December 2024), paragraphs 30 and 50–54.

Key Terms

• Scope 3 Category 6 — Business travel emissions: indirect emissions from transport and accommodation used by employees for work purposes.
• Radiative forcing (RF) uplift — A multiplier applied to flight emissions to account for non-CO₂ warming effects of aviation at altitude. DESNZ uses 1.7 as a central estimate; the value is uncertain and other sources use different figures, so say which you applied.
• Emission factor — The average CO₂e released per unit of activity (e.g. per passenger km, per night).
• VSME B3 — The VSME Standard disclosure covering energy use and greenhouse gas emissions. It requires Scope 1 and location-based Scope 2; Scope 3 (including business travel) is optional in both modules.
• ESRS E1-6 — The ESRS disclosure requirement for gross Scope 1, 2 and 3 and total GHG emissions.
• Distance-based calculation — Preferred method: total distance (km) × emission factor per km.
• Spend-based calculation — Fallback method: total spend (€) × emission factor per €, used when distance data is unavailable.

Conclusion

Reporting business travel emissions is straightforward once you identify your data sources and choose the right calculation method. Start with what you have — invoices, expense reports, booking confirmations — estimate gaps using documented assumptions, and disclose your methodology clearly.

Over time, investing in centralised travel booking and better record-keeping reduces estimation uncertainty and makes your figures easier to defend when a customer looks closely. Even in Year 1, a well-documented estimate is a credible starting point.

Calculate the figure once and keep it working: an ESG answer bank stores your travel emissions with their methodology, ready for every future questionnaire, and a free VSME report tool builds the finished report from those answers at no cost.