A form of independent demand item management model in which an order for a fixed quantity is placed whenever stock on hand plus on order reaches a predetermined reorder level. The fixed order quantity may be determined by the economic order quantity, by a fixed order quantity (such as a carton or a truckload), or by another model yielding a fixed result. The reorder point may be deterministic or stochastic, and in either instance is large enough to cover the maximum expected demand during the replenishment lead time. Fixed reorder quantity models assume the existence of some form of a perpetual inventory record or some form of physical tracking, e.g., a two-bin system that is able to determine when the reorder point is reached. Synonym: Fixed Order Quantity System, Lot Size System, Order Point-Order Quantity System, Quantity Based Order System. Also see: Fixed Reorder Cycle Inventory Model, Hybrid Inventory System, Independent Demand Item Management Models, Optional Replenishment Model, Order Point – Order Management System.