Estimate the carbon footprint of a conference, trade show, offsite or festival from how attendees travel and stay, with UK Government (DESNZ) conversion factors, then offset it in a few clicks.
Custom leaves every value below for you to enter. The other types fill in typical travel and stay values as starting points, not data about your event. Change any of them. Fields marked * are required.
Required. An event type never fills this in; there is no footprint without it.
Only countries DESNZ publishes a hotel factor for are listed.
Getting there · round trips
Under 3,700 km uses the short-haul band.
Staying over
The DESNZ hotel factor is per room per night. 1 counts a room for each person staying; 2 halves the room count.
These need figures from the venue or your suppliers. Leave them at zero and the result covers travel and accommodation only, usually the large majority of an event’s footprint.
Valued at the UK grid factor wherever the event is; see the methodology.
Catering
Attendees × days × meals a day. Each meal is valued at a third of a day of eating for the menu type (Scarborough et al. 2023, Nature Food).
Enter attendees and how they travel to see a footprint
Start with the attendee count and the shares arriving by air or ground, or pick an event type for typical values. Travel, accommodation, venue energy, materials and waste are each valued with UK Government (DESNZ) 2026 conversion factors.
An event’s footprint is the sum of a few large legs, mainly attendee travel, hotel nights and venue energy, plus a tail of small ones. Each leg is an activity (kilometers, room-nights, kilowatt-hours, kilograms) multiplied by a published conversion factor. The tool asks for the activities a planner can know or estimate, applies the factors, and shows its working.
Every coefficient comes from the Greenhouse gas reporting: conversion factors 2026, published by the UK Department for Energy Security and Net Zero (DESNZ/DEFRA) on 11 June 2026. It is the reference set for UK statutory carbon reporting and widely used for voluntary disclosure. Each coefficient is listed with its workbook row under the result.
The air leg uses the same DESNZ factors, radiative forcing and 8% great-circle uplift as the Carbonmark flight emissions calculator, so a footprint built here agrees with one built there. The haul band follows from the average distance.
For most in-person events, attendee travel is the majority of the footprint and accommodation most of the rest. The tool asks for those first and treats venue energy, materials and waste as optional extras that need figures from the venue.
Custom, the default, fills in nothing: you enter every share and distance yourself. The event-type presets (shares flying and driving, average distances, hotel nights) are typical mixes, not data about your event, and every field stays editable. Car travel assumes 1.5 occupants per vehicle. Hotel rooms are counted at 1 person per room unless you say otherwise, because the DESNZ factor is per room per night. Venue electricity is valued at the UK grid factor wherever the event is, because that is the only grid factor DESNZ publishes.
DESNZ publishes no per-meal factor, so catering draws on two sources a reviewer can open. By meals: Scarborough et al. 2023, Nature Food, the median dietary emissions per person per day for six diet groups among 55,504 UK adults, divided by 3 meals a day, which is our derivation and is labeled as one. By spend: the US EPA Supply Chain GHG Emission Factors v1.3 row for caterers, per 2022 US dollar. Use meals when you know the menu; it rewards the one catering choice you control.
Local transport within the host city, staging and shipped exhibits are excluded because they need event-specific data. The result is a traceable estimate of the main legs, not a full inventory.
Figures are estimates for planning and communication. For a formal inventory, reconcile the factor basis with your reporting framework, or talk to our carbon accounting team. Flying to the event? The flight emissions calculator gives a per-passenger figure for a specific route.
This tool is one example of the carbon accounting integrations we build for partners. It is lightweight to embed, backed by recognized emissions coefficients, and connected to real-time offsetting through the Carbonmark API.