Flow

WIPWork In Process

Inventory that has entered production but is not yet finished — the lever that controls lead time via Little's Law.

Work In Process (WIP) is all the partially completed inventory between raw material and finished goods. Some WIP is needed to keep steps decoupled, but excess WIP lengthens lead time, ties up cash, and hides defects.

Per Little's Law (WIP = Throughput × Lead Time), capping WIP is the most direct way to shorten lead time — the principle behind kanban and CONWIP.

Go Deeper
WIP / Little's Law Calculator→Little's Law guide→
Related Terms
Little's Law
A fundamental relationship: WIP = Throughput × Lead Time, explaining why cutting WIP shortens lead time.
Lead Time
The total elapsed time from order (or raw material) to delivery (or finished product), including all waiting.
Throughput
The rate at which a system produces finished, sellable output — ultimately limited by the bottleneck.
Kanban
A visual signaling system that triggers production or replenishment based on actual consumption rather than forecasts.
CONWIP
A pull system that caps the total work-in-process in a line, releasing new work only as finished work exits.
Inventory
Raw materials, work-in-process, and finished goods held in the system — one of the eight wastes when excessive.

Put WIP into practice

SymplProcess turns these concepts into working models, calculators, and templates your whole team can use — no spreadsheets required.

Open the App → Try the Process Modeler
← Browse all glossary terms