The GHG Protocol is the world’s most widely used carbon accounting standard, dividing emissions into Scope 1 (direct), Scope 2 (purchased energy) and Scope 3 (value chain, 15 categories). WeZero is structured around the protocol: it records your consolidation approach, applies UK Government (DESNZ) conversion factors pinned to the correct reporting year, and shows the activity data, factor and calculation steps behind every figure for full transparency. Subsidiary tagging supports entity-level and group reporting. The same dataset produces SECR tables, Carbon Reduction Plans, NHS Evergreen evidence and net-zero target pathways. The core calculator is free.