This guide for quantification of health commodities has been developed to assist technical advisors, program managers, warehouse managers, procurement officers, and service providers in (1) estimating the total commodity needs and costs for successful implementation of national health program strategies and goals, (2) identifying the funding needs and gaps for procurement of the required commodities, and (3) planning procurements and shipment delivery schedules to be able to ensure a sustained and effective supply of health commodities. The step-by-step approach to quantification presented in this guide is complemented by a set of product-specific companion pieces that provide detailed instructions for forecasting consumption of ARV drugs, HIV test kits, antimalarial drugs, and lab supplies.