An initial estimation: using the company's accounting files, GHG emissions are estimated for the 3 Scopes via a monetary approach. This initial estimation can be carried out almost instantaneously, since accounting files have already been formatted and annotated by the company's financial teams. The purpose of this initial estimation is to identify the most significant emission sources so that calculations can be fine-tuned at a later stage.

A fine-tuning stage: by collecting physical data (kg/lbs purchased, km/miles travelled, L/gallons consumed, etc.), GHG emissions of the most significant sources that were previously identified are specified using an activity-based approach. This step is crucial because it enables to fine-tune results and recommend concrete action plans.