Business Travel Carbon Footprint & Offset Audit

Calculate business travel CO2 emissions across train, flight, and car using official emission factors and tree offset values.

Carbon footprint of a business trip: plane, train or car

The tool multiplies the distance travelled by an ADEME emission factor per kilometre and per person, specific to each mode, then adds 14.5 kg CO2e per hotel night. An 800 km return trip by short-haul flight thus emits 359 kg CO2e per traveller, against 3.7 kg by high-speed train, about 97 times less.

The formula

Emissions (kg CO2e) = one-way distance × 2 for a return trip × mode factor × travellers (for cars, × number of vehicles: one per 5 travellers) + hotel nights × 14.5 × travellers. ADEME factors applied, in kg CO2e per km per person: high-speed train (TGV) 0.0023; short-haul flight (under 1,000 km) 0.2242 and long-haul flight (over 3,500 km) 0.1776, contrails included; petrol or diesel car 0.1106 and electric car 0.0121, manufacturing included. From this the tool derives tonnes emitted, a number of trees (emissions ÷ 25 kg absorbed per tree per year, rounded up) and an offset cost at the price per tonne you enter (€35 by default).

Default example

800 km one way by short-haul flight, return trip, one traveller, two hotel nights: 1,600 × 0.2242 = 359 kg for the flight and 2 × 14.5 = 29 kg for the hotel, i.e. 388 kg CO2e (0.388 t), 16 trees and €13.58 of offsetting. By TGV the journey emits 3.7 kg, 33 kg with the hotel; the tool shows 355 kg avoided, 91.5% less.

Assumptions and limits

  • By car, travellers share the vehicle: emissions are counted per car, one per 5 travellers, as ADEME splits a vehicle's emissions between its occupants.
  • No medium-haul factor (1,000 to 3,500 km) is offered, and the train alternative uses the same distance, even where there is no rail link.
  • The 14.5 kg per hotel night and 25 kg absorbed per tree are indicative values, not verified; offsetting does not cancel emissions.

An awareness estimate, separate from a regulatory greenhouse gas emissions report.

Sources and dates: transport factors published by the Impact CO2 service of the French agency ADEME, consulted on 14/10/2026 (publication date not stated) (checked 14/10/2026).

Frequently Asked Questions

How much CO2 does an 800 km return flight emit?

Using ADEME's short-haul factor (0.2242 kg CO2e per km per passenger, contrails included), 1,600 km give 359 kg CO2e per traveller. Two hotel nights bring the displayed total to 388 kg, or 0.388 tonnes.

Why does the train emit so little in this calculation?

ADEME uses 0.0023 kg CO2e per km per traveller for France's TGV, about 97 times less than a short-haul flight, thanks to France's low-carbon electricity. Over 1,600 km the train emits 3.7 kg; on a trip with a hotel stay, the nights then weigh the most.

How does the tool calculate the carbon offset cost?

It multiplies the tonnes emitted by the price per tonne you enter, €35 by default: 0.388 t gives €13.58. Real carbon credit prices vary widely between projects, and offsetting does not erase emissions already produced.

How should I count colleagues sharing a car?

Enter the number of travellers: the tool counts one car per 5 people and does not multiply its emissions by the passengers. For three colleagues in one petrol car over 1,600 km, the journey weighs 177 kg in total, or 59 kg per person, as in ADEME's method.

Is this tool really free?

Yes, all tools on Kristools are 100% free and accessible without registration.

Is my data protected?

Yes. All processing is performed directly and securely inside your browser. No personal data is sent to our servers.