The Toolbox, an initiative of 11th Hour Racing, is suite of guides, tools and templates created to make sustainability strategy free and accessible for any organization, no matter the size or industry sector.
It includes a DIY GHG calculator providing a series of spreadsheets as trackers, and you would then piece together your measurement through the overall carbon calculator sheet. The EFs are 2021 so you may need to update those in the back end or adjust if you want to use more precise EFs.
The GHG calculator is set up for monthly data, and so not created specifically for events, rather for organisations, but there is a lot of functionality a DIY GHG measurer could draw on.
