SPECTRUM Generalized Cost-Effectiveness Analysis (GCEA) is a tool developed to facilitate country-level cost-effectiveness analysis of a wide range of health interventions. The tool is populated with country-specific default information on epidemiology and estimated costs (quantities and prices). Country analysts can contextualize their cost-effectiveness analyses by changing default epidemiology and cost data to more locally relevant ones. If they wish, they can then proceed to assess health system implications and financial costs, using the OneHealth Tool to inform the design of health benefit packages and overall health strategies. The availability of cost-effectiveness analysis in the same platform as the OneHealth Tool allows users to apply the same set of impact models and cost data for both types of analysis.