This document specifies requirements for calculating the carbon footprint specific to farmed macroalgae product category rules (CFP–PCR). This methodology builds on the requirements of International Standards for life cycle assessment (LCA) and products’ carbon footprints. This document is applicable to the calculation and communication of farmed macroalgae products’ carbon footprints from seedling cultivation to the consumption of macroalgae products. It is applicable to the carbon footprints of products from aquaculture value chains. This document used alone does not apply to specifying a product’s overall environmental or sustainability characteristics.