Event Carbon Footprint Calculator

The calculator estimates CO₂-equivalent (CO₂e) emissions across four main categories: transportation (flights, car, train, bus), accommodation (hotel nights), catering (meat vs. vegetarian vs. vegan meals), and venue energy (heating and air conditioning). Each category uses established emission factors from sources like IPCC, DEFRA, and myclimate. All figures are summed to give a total footprint in kg CO₂e. See also our Lifecycle Carbon Assessment Calculator (LCA).

Shifting some attendees to remote or hybrid participation significantly cuts transport emissions, which are typically the largest contributor. Even moving 20–30% of attendees online can reduce total footprint by a meaningful amount. Choosing a central venue accessible by train also helps reduce reliance on flights and cars.

Encourage participants to travel by train or bus instead of flying, especially for short-haul distances under 500 km. Organise group shuttle services to reduce individual car use. Choosing a venue close to an international hub reduces the need for long-haul flights. Offering bike parking and proximity to public transport encourages low-carbon last-mile travel.

Look for venues with green energy certification (e.g. 100% renewable electricity), good insulation to reduce heating and cooling loads, and proximity to public transport. Smaller, well-insulated rooms for the actual attendance size are more energy-efficient than large under-utilised spaces. Some venues offset their operational emissions — ask your venue provider directly. You might also find our Supply Chain Emissions Calculator useful.

Food is a significant but often overlooked emission source. A standard meat-based meal generates roughly 3–5 kg CO₂e per person per day, while a vegetarian meal is around 1.5–2 kg CO₂e and a vegan meal around 0.8–1.2 kg CO₂e. Offering predominantly plant-based menus, reducing food waste, and sourcing locally can cut catering emissions by 50% or more.

CO₂e stands for 'carbon dioxide equivalent.' It's a standard unit that expresses the global warming potential of all greenhouse gases (CO₂, methane, nitrous oxide, etc.) in terms of the equivalent amount of CO₂. Using CO₂e allows different emission sources — flights, food, energy — to be compared and summed on a single consistent scale.

Once you know your total CO₂e, you can purchase verified carbon offsets through certified providers (e.g. Gold Standard, VCS). Offsets fund projects like reforestation, renewable energy, or methane capture. However, best practice is to reduce emissions first and only offset what remains unavoidable. Communicating your footprint and offset actions to attendees builds trust and awareness.

Aviation has very high emission factors per kilometre — a single transatlantic return flight can generate 1,000–3,000 kg CO₂e per passenger. Even a small percentage of attendees flying long-haul can dominate the total footprint. This is why replacing one or two key long-haul flights with virtual attendance often delivers the single biggest emissions reduction available to event organisers.