WIP inventory is material or product that has entered production but is not yet finished goods.
WIP inventory is the material, parts, assemblies, or products that have entered a production process but have not yet been completed as finished goods. WIP stands for work in process or work in progress; in manufacturing, both phrases commonly refer to partially completed production.
WIP inventory may include items being processed at a workstation, waiting between operations, held for inspection, or queued for rework or disposition. It is distinct from raw material inventory, which has not yet started production, and finished goods inventory, which has completed required production and release steps.
In MES, ERP, and production planning contexts, WIP inventory is used to track quantities, locations, status, routing progress, cost accumulation, and traceability through the shop floor. For example, a machined component that has completed milling but is waiting for inspection before assembly is typically counted as WIP inventory.