Event calculator
Built around one event: registrations, travel, hotels, catering.
Quick; may not feed the annual inventory.Software · event carbon, buyer’s guide
Event carbon software: an organiser’s buying guide
Event carbon software turns registrations, attendee travel, hotel nights, venue energy and catering into a footprint for an event.
This page sorts the three kinds of tool, lists what to ask venues and suppliers for, and gives the demo questions to run on a past event.
What a footprint contains, category by category, is on event carbon reporting software.
Three kinds of tool
Which kind of event carbon software does an organiser need?
The right tool depends on whether the event footprint stands alone or feeds the company’s annual figures.
An event calculator answers one event quickly; a corporate platform puts the event into the inventory under the Scope 3 Standard; a venue tool covers the venue and nothing else.
Many organisers use two: the venue’s data feeding their own calculator or platform.
Event
data
data
Corporate platform
An event module inside the company’s carbon accounting.
Joins up with Scope 3; heavier to set up.Venue tool
The venue’s own reporting of energy and waste for your dates.
Good venue data; covers only the venue.Before the event
What should an organiser ask venues and suppliers for before the event?
Most event footprints are only as good as the data requested before the doors open.
Ask the venue for metered energy for your dates and waste weights by stream, and ask the caterer for quantities, because none of that is easy to recover afterwards.
Add home country or postcode and travel mode to the registration form, which lets the tool calculate travel by distance rather than by spend.
DESNZ publishes hotel stay factors by country in its conversion factors, so room nights by country are enough for that line.
Data to request in advanceExplore
Data to request in advance
Venue energy
Metered kWh for your dates, not a share of the year.
Data to request in advance
Waste by stream
Weights for residual, recycling and food waste.
Data to request in advance
Catering
Menus and quantities, or the caterer’s own figures.
Data to request in advance
Travel
Home country or postcode and mode, at registration.
Before you buy
Which questions should you put to an event carbon provider?
Each question beside this names its source and what a passing answer looks like.
Bring last year’s registration export and venue invoice, because a demo event never has missing postcodes.
The full category-by-category method is on event carbon reporting software.
This site has tested no products
Nothing here is a rating, ranking or recommendation.
Event carbon demo questions · tick the ones you need
The pass tests are our reading of the cited provisions.
Nothing you tick is stored or sent.
The platforms
Which platforms might suit an event organiser, in their own words?
The registry has no event category. This list is the vendors filed under small businesses, plus Unravel Carbon, whose product footprint page says it covers “physical goods and events”.
Alphabetical, which ranks nothing; each describes its own offer clearly.
Each line is the platform’s own description, linked to the page it is on, read 11 October 2026 and 30 September–1 October 2026. Alphabetical; nothing here is a rating.
14 platforms, own wordsExplore
14 platforms, own words
Event as its own footprint
Ask to see one event reported alone.
14 platforms, own words
Event in the inventory
Ask to see the same lines in annual Scope 3.
14 platforms, own words
Registration import
Ask which ticketing exports it reads.
Spreadsheet or software
When is a spreadsheet enough for an event footprint?
One event with clean registration data can be calculated in a spreadsheet with the DESNZ factors.
A programme of events, or a venue hosting many, makes the case for a tool that reuses the same set-up each time.
The calculator beside this compares the hours your current method takes with any quote you hold; it names no price.
Platform against the way you work now
Current process £0 a year · quote £0 a year
Fill in all three to see the break-even hours.
Arithmetic on your own inputs.
The quote’s implementation, uplift and exit terms are in the three-year worksheet on the carbon reporting software page.
Nothing is stored or sent.
The event timeline
When does event carbon work happen, from booking to report?
Put the data request into the venue and catering contracts at booking, when you have the most leverage.
Collect travel data at registration, not in a survey afterwards that half the audience ignores.
Calculate within weeks of the event, using the factor set for the year it happened.
One eventExplore
One event
Booking
Ask the venue and caterer for data in the contract.
One event
Registration
Collect origin and travel mode.
One event
Event days
Venue meters and waste weighed.
For the board
An event footprint is decided at booking and only counted afterwards
Choose the tool that makes the data request easy, because that is where the accuracy comes from.
Takeaways
Event carbon software in five facts
| Fact | What to do |
|---|---|
| No UK duty this site tracks requires an event footprint | Buy for the client or sponsor who asks |
| ISO 20121:2024 is a management-system standard | Use the tool as evidence, not as the standard |
| DESNZ publishes hotel stay factors by country | Collect room nights by country |
| Travel data is easiest at registration | Add origin and mode to the form |
| Venues hold the energy and waste data | Write the data request into the contract |
Next: read BAFTA albert certification if your events are in film and TV production.
Frequently asked
Event carbon software, answered
What is event carbon software?
Software that turns the data an event generates — registrations, attendee travel, hotel nights, venue energy, catering, production and waste — into a carbon footprint for the event.
The sibling guide on event carbon reporting software sets out what a footprint contains; this page helps an organiser choose a tool.
Which event carbon software is best?
This site has tested no product and names no best.
Choose the kind of tool first — an event calculator, a corporate platform with an event module, or the venue’s own tool — then run the demo questions on a past event’s data.
Is there a legal requirement to measure an event’s carbon footprint?
None of the UK duties this site tracks requires an event footprint.
SECR asks for no Scope 3 beyond transport fuel.
Buyers, sponsors and public-sector clients may ask for one, and PPN 006 applies to major government contracts as procurement policy.
What does ISO 20121 have to do with event carbon software?
ISO 20121:2024 is a management-system standard for event sustainability that applies to events of all types and sizes.
It names self-declaration, supplier validation and third-party certification as ways to show conformity.
A carbon tool can supply evidence for it but is not the standard.
Which emission factors should event carbon software use?
For UK reporting, the DESNZ conversion factors for the year the event took place, which include hotel stay factors by country.
DESNZ says its 2026 factors are for activity falling entirely or mostly within 2026.
What should I ask the venue for?
Metered energy for your dates, waste by stream, and what the venue’s own sustainability tool already reports, so you do not count the same thing twice.
How do I capture attendee travel?
Usually from registration data: home country or postcode and the travel mode, then a distance-based calculation.
A post-event survey can replace estimates with reported journeys.
Can a corporate carbon platform handle events?
Some describe event coverage directly; Unravel Carbon’s product footprint page, for example, says its tool covers physical goods and events.
Ask any platform to show an event as its own footprint and as part of the annual inventory.
Can I call my event carbon neutral?
Any public claim needs to be accurate and substantiated, as the CMA’s Green Claims Code sets out.
A tool should tie the claim to the calculation and say what it covers.
Is a spreadsheet enough for one event?
Often yes, for a single event with good registration data.
Software earns its place for a programme of events or a venue that hosts many.
Does the event footprint go into the company’s report?
If the company reports Scope 3, the event’s emissions belong in the relevant categories, such as business travel and purchased goods and services.
A tool should feed the annual inventory rather than sit apart from it.
Sources
Primary sources
Every figure, date and status on this page traces to the instrument’s owner.
Secondary commentary is never the source for a number.
Checked against 15 sources fromISODESNZGHG Protocollegislation.gov.ukCabinet OfficeDBT
- ISOISO 20121:2024 Event sustainability management systems
Edition 2, April 2024; all event types and sizes.
- DESNZGovernment conversion factors for company reporting
One set per activity year, including business travel and hotel stay.
- DESNZGreenhouse gas reporting: conversion factors 2026
Published 11 June 2026; flat file corrected July 2026.
- DESNZ2026 conversion factors methodology paper, ¶1.10
Use the factors for the year the activity took place.
- DESNZ2026 conversion factors: major changes report
Why some factors moved between years.
- GHG ProtocolCorporate Accounting and Reporting Standard
Boundaries and principles.
- GHG ProtocolCorporate Value Chain (Scope 3) Standard
The fifteen Scope 3 categories.
- GHG ProtocolScope 3 calculation guidance
Methods by category: distance, spend, supplier-specific.
- legislation.gov.ukSI 2008/410, Schedule 7 (SECR)
No Scope 3 beyond transport fuel.
- Cabinet OfficePPN 006: carbon reduction plans
Procurement policy for major government contracts.
- DBTUK SRS S2 Climate-related Disclosures (PDF)
Scope 3 disclosure for companies that report against UK SRS.
- FCAPS26/19
Comply or explain for listed companies in five categories.
- GOV.UKGreen Claims Code
For “carbon neutral event” claims.
- ISOISO 14064-1
Organisation-level quantification, for comparison.
- Unravel CarbonProduct carbon footprint
The owner’s description, which names events.
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