This paper presents an overview of a force readiness simulation tool that has been developed for the Canadian Forces (CF). The Managed Readiness Simulator (MARS) is a versatile program that allows the user to quickly simulate a wide range of scenarios to forecast the extent to which the resources of an establishment are available to fulfill the requirements of a set of planned tasks over time. MARS can also account for the dynamics of the establishment, including recruitment, promotion, and attrition of personnel, and acquisition, maintenance and disposal of equipment. Two examples of how MARS has been applied to current CF problems are also included.