A customizable scheduling tool is used in a system for managing and controlling manufacturing processes planned by enterprise resource planning (ERP) and produced by a plant floor. A manufacturing executing system (MES) implements the planned manufacturing process and controls the corresponding production at the plant floor. The scheduling tool contains a set of built in data relating to the plant floor forming a data model and built in formula templates. The scheduling tool contains measures for defining new data, and the measures are operable to edit new fields to expand the built in set of data, and measures for modifying a built-in formula template. Ideally a manufacturing executing system (MES) contains such a tool and utilizes a method of using the tool.