Reuse platforms are contributing to the circular economy by hosting or mediating unwanted products or materials until new users are found. This saves products from premature disposal on one hand, and avoids new products purchase on the other. Translating this resource efficiency and waste minimisation into GHG emission avoidance can support the relevance of reuse platforms in fostering a circular economy and promoting climate protection through resource preservation and potential GHG emission reductions. The authors present the analysis of existing reuse methodologies and point out incomplete considerations in terms of LCA modules and Corporate Carbon Footprint of reuse platforms [11]. This paper fills the gap in literature by formulating a holistic methodology for calculating benefits of reuse in terms of GHG emissions for the whole reuse sector and provides an application guide for 4 different types of reuse platforms. This new approach is then illustrated by applying it to a reuse enterprise Zündstoffe Materialvermittlung Dresden (ZUMADD) case study, for which data was gathered for 2 years under Dresden Future City Project (2019–2022). The results show that the project could save 13,301 kg of CO₂e emissions through mediating 6,213 kg of material for reuse.