This paper provides documentation, at a detailed mathematical level, of the portion of the Risk Assessment and Mitigation Framework for Strategic Materials (RAMF-SM) that calculates demands for strategic and critical materials. Two different algorithms to compute material demand are described. The more commonly used one involves quantities called material consumption ratios, which are generally based on data from the Department of Commerce and the Department of the Interior. An alternative algorithm is used for materials with intensive defense demands. Developed by the Institute for Defense Analyses, RAMF-SM has played a key role in the analyses that have supported the Reports to the Congress from the Department of Defense concerning requirements for the National Defense Stockpile of strategic and critical non-fuel materials.