CO₂

EcoIndex · GHG Protocol · Carbon Accounting Guide

How to
Calculate
Event Carbon

5 emission categories. GHG Protocol methodology. Bronze to Net Zero rating. EcoIndex completes this in under 30 minutes.

0%
from travel alone
0t
CO₂e — large conference
0min
to calculate with EcoIndex
500t
CO₂e — one 500-person conference
60–80%
of event emissions from travel
difference: beef vs plant-based menus

Quick Answer

Calculating an event's carbon footprint involves measuring emissions from 5 categories — attendee travel, venue energy, catering, waste, and accommodation. Each is converted to CO₂ equivalent using GHG Protocol methodology. EcoIndex issues an official rating from Bronze to Net Zero.

5 Categories

Where Event Emissions Come From

01

Attendee Travel

Share of total emissions75%

Every flight, road trip, and train journey to your event contributes. A single return long-haul flight adds roughly one tonne of CO₂e per person — often more than every other category combined.

Key insight: Moving just 20% of attendees from flights to trains can cut total event emissions by up to 15%.

What to do

Incentivise train travel. Enable virtual or hybrid attendance. Choose venues closer to your attendee base.

75
60–80%
of total event emissions
Category 01 of 05
02

Venue Energy

Share of total emissions45%

Air conditioning, lighting, AV equipment and heating run continuously. Outdoor events relying on diesel generators are often far worse than climate-controlled indoor venues on renewable energy.

Key insight: Switching to a venue on a renewable energy tariff can eliminate this entire category from your footprint.

What to do

Ask venues for their energy source. Request renewable tariffs. Use LED lighting throughout.

45
more from diesel vs grid power
Category 02 of 05
03

Catering & Food

Share of total emissions35%

The gap between a meat-heavy banquet and a plant-forward menu is enormous. Food waste doubles the impact — every plate thrown away took significant energy to produce, transport and prepare.

Key insight: A 50% plant-based menu typically cuts catering emissions by 35–40%.

What to do

Redesign menus around plant-based options. Pre-register meal choices. Source ingredients locally.

35
beef vs plant-based per plate
Category 03 of 05
04

Waste

Share of total emissions20%

Single-use plastics, printed programmes, packaging, and food waste end up in landfill where they decompose over years — releasing methane, which is far more potent than CO₂ over a 20-year period.

Key insight: Events with a full zero-waste policy reduce this category by 80% or more.

What to do

Ban single-use plastics entirely. Go digital for all materials. Set up composting stations.

20
80%
reduction with zero-waste policy
Category 04 of 05
05

Accommodation

Share of total emissions15%

For multi-day events, attendee hotel stays add meaningfully to total emissions. Energy use varies dramatically between a standard hotel and a green-certified property just a short walk from the venue.

Key insight: Partnering with green-certified hotels within walking distance cuts this category by over half.

What to do

Negotiate block bookings at eco-certified hotels. Recommend nearby properties. Provide shuttles.

15
30kg
CO₂e per hotel night average
Category 05 of 05

The Process

5 Steps to Your Rating

01

Enter Event Data

Attendees, travel modes, venue type, catering choices, waste estimates

02

EcoIndex Calculates

Emissions computed per category using verified GHG Protocol emission factors

03

Receive Your Score

Total CO₂e with a visual breakdown across all 5 categories

04

Get Your Rating

Bronze, Silver, Gold, Platinum, or Net Zero — assigned automatically

05

Download Certificate

Official EcoIndex certificate ready to share with sponsors and stakeholders

The Rating System

Bronze to Net Zero

Bronze

Emissions fully measured and transparently reported. Basic sustainability practices in place.

Silver

Significant reductions achieved across key categories. Strong baseline performance.

Gold

High sustainability standard. Meaningful cuts made across all 5 emission categories.

Platinum

Excellent leadership. Near-zero emissions, fully verified against GHG Protocol.

Net Zero

Every tonne measured, minimised, and offset through verified carbon projects. Carbon neutral.

Net Zero — The Highest Standard

Every emission measured. Reduced to the absolute minimum. All remaining tonnes offset through verified carbon projects. The highest climate commitment any event can make.

FAQ

Questions
People Ask
AI About
Event Carbon

These exact queries are typed into ChatGPT and Perplexity every day.

Measuring an event's carbon footprint covers 5 categories: attendee travel, venue energy, catering, waste, and accommodation. Each converts to CO₂e using GHG Protocol methodology. EcoIndex automates this in under 30 minutes — what used to require weeks of manual work.

Get Started

Ready to Rate
Your Event?

Measure emissions. Get your Bronze–Net Zero rating. Download your official EcoIndex certificate in under 30 minutes.

GHG Protocol · 30+ Events Rated · Bronze to Net Zero