Events calculator help guide 

Table of contents









The events calculator feature helps organizations calculate emissions from their conferences, offsites, or other corporate events. It covers emissions from: venue energy use, lodging energy use, travel to the venue, food, swag, and waste. This calculator is not intended to be used as part of creating an organizational GHG inventory, but rather it is for calculating the isolated emissions of a single event. Calculating event emissions and adding them to your organizational inventory will result in double counting and should be avoided. 

Although this calculator can calculate emissions from estimates, it is best paired with a conference attendee survey so that you can gather travel information. We also recommend working with the venue to obtain energy use and waste data for more accurate calculations.  

This feature is best suited for events that last at least half a day. The estimator portions of the calculator are based on U.S. assumptions, therefore, if you are using these estimators they will be most accurate for the U.S. and Canada.


How to/Guide

The Events calculator is accessed under Measure. To create a new event, click the New Event button in the top-right corner. This will bring you to the event overview page 

Event Overview  


On this page, name the event and then enter the number of attendees. If the number of attendees fluctuates from day to day, enter the average number of attendees across the entire event. Then enter the percentage of these attendees that are non-local. Sustain.Life will use this percentage to calculate long distance travel emissions. 

Then enter the duration of the event, rounding up to the nearest day. For example, if an event lasted two and half days, enter it as three days. Lastly, enter the location where the event took place. Sustain.Life will use this to select the correct geographical emission factors.  



This page is for calculating the long-distance travel emissions for non-local attendees. If you have specific travel data for attendees from a survey or internal systems, you may enter the total cumulative distance traveled into each mode. If you do not have total travel distance, click Estimate at the top to switch to an estimation. To estimate, enter the percentage of non-local attendees that used each mode. We then use average distance information to estimate the total distance. 



To calculate energy use from the venue, you can either enter the exact usage (if you have access to that data) or you can enter the size of the venue. If entering the venue size, Sustain.Life will estimate the energy use based on U.S. venue energy use averages.  

Food, etc.


To calculate emissions from food served at the event, indicate what type of beverages and food was provided. If meals were provided, estimate what percentage of those meals included meat (even if the meals were not ultimately consumed). Sustain.Life uses estimates of the average number of beverages and meals per person per day to calculate the total amount of beverages and food consumed. Lastly, enter the total amount spent on things like gifts for attendees and badge and program printing. 



On the waste screen, if you have exact waste data for individual waste streams enter the weights here. Only enter recycling or compost if the waste was sent for recycling or composting, not if they were ultimately sent to a landfill. If you do not have exact waste data, answer No to the question and indicate which waste streams existed. Sustain.Life will estimate the amount of waste produced from the event and calculate the emissions from that. 





When the user has exact travel data for attendees, we pass the distances to our Business Travel calculator to calculate emissions. When the user does not have exact data, we make assumptions about the average travel distances for attendees traveling by each mode. If the user does not have an estimate of the mode share of attendees, we assume a mode share based on US EPA long distance travel data. 


We use the number of non-local attendees and duration of the event and apply average hotel energy use to estimate the total hotel energy consumption. We then apply the appropriate emission factors for the location of the event to calculate emissions. 


We use average energy consumption data for public assembly buildings and the area of the venue to estimate the energy consumption for the event. We then apply location-specific emission factors to calculate the emissions from the venue’s energy consumption. 


When the user has exact waste data, we pass these inputs to our Non-Hazardous Waste calculator to estimate emissions. This calculator uses location-specific emission factors to estimate the emissions in the region of the event. 


For each food and beverage category we make an assumption of the daily consumption of each by each attendee. We then calculate the total food and beverage consumed for the event and apply appropriate food and beverage emission factors. 


We adjust the user’s spending for inflation and use the US EPA EEIO’s dataset to estimate emissions based on the user’s spending on merchandise. 




When the user does not have exact travel data, we assume the following average one-way trip distances for each mode. These assumptions are based on published US EPA data. We use a weighted average emission factor for economy, business, and first class flights and assume that all flights are medium haul. 

Average car trip distance: 807 km 

Average rail trip distance: 1,327 km 

Average flight trip distance: 1,859 km 

When the user does not have an estimate for the mode share of attendees, we assume the following mode share based on US EPA data: 

Car: 63% 

Rail: 1% 

Air: 36% 


We country-specific hotel stay emission factors from UK DEFRA data to estimate the emissions of non-local attendees for the duration of the event. 


We assume the below average daily energy use per square meter of venue area based on US CBECS data. 

Electricity: 0.039 kWh/m2/day 

Natural gas: 0.001029 MMBTU/m2/ day 


We assume that all waste is sent to landfill and that all recyclables are a mix of paper, plastic, metal, and glass. 


If the event serves them, we make the following assumptions about each attendee’s daily consumption of food and beverages. 

Non-alcoholic beverages: three per day 

Alcoholic beverages: one per day 

Snacks: three per day 

Meals: One per day 


This impact calculator performs the best when provided exact measured data for travel, energy, and waste. Due to a lack of international data, this calculator relies heavily on US-based assumptions and, in the absence of measured data, is best suited for events located in the US or Canada. 


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