The report of the Independent Evaluation Unit on the “Adaptation Portfolio and Approach of the GCF” identified clearly the main gaps related to the lack of a clear methodology for estimating the “number of direct and indirect beneficiaries” of adaptation projects from the GCF portfolio: challenges for project comparison and aggregation, over-estimation of beneficiaries and no indication on the depth of the impact.Against this backdrop, this project aimed at developing a robust methodology for future estimation of the total number of direct and indirect adaptation beneficiaries of GCF projects. The project team developed a framework that can be applied widely to estimate the number of beneficiaries and identified areas which require further work to achieve a comprehensive methodological approach. An indicator considering the depth of adaptation impact was created: the impact weighted number of beneficiaries. The methodology developed was applied ex-post to the adaptation and cross-cutting projects of the 119 projects approved by B29. Lessons learned from this ex-post estimation were used for strengthening the methodology.