This Guidance document facilitates commonly understood and harmonised Scope 3 GHG emission calculations within the primary aluminium value chain. It is based on the Corporate Value Chain (Scope 3) Accounting and Reporting Standard, containing a materiality assessment for 15 categories in each primary aluminium value chain production step. This Excel-based Tool utilises the user’s input data and publicly available emission factors to generate an indicative result and can also be used together with aluminium sector-specific tools that are available on the GHG Protocol website.