This document summarizes an analysis conducted by the UN Food and Agriculture Organization on estimating required investments in agricultural extension services to achieve zero hunger and climate change adaptation goals. It describes the methodology used, which involves developing a country-specific formula to calculate the needed number of extension agents based on socioeconomic indicators. Sample results are provided for several countries showing current spending, estimated required investments under baseline and climate change scenarios, and the gap. Regional averages are also estimated. The document discusses limitations and makes recommendations to improve data quality and test more efficient investment approaches.