Flow

Little's Law

A fundamental relationship: WIP = Throughput × Lead Time, explaining why cutting WIP shortens lead time.

Little's Law states that the average work-in-process in a stable system equals its throughput multiplied by its average lead time (WIP = TH × LT). It holds for any stable process regardless of complexity.

Its practical punch: if you want shorter lead time at a fixed throughput, you must reduce WIP. This single relationship justifies WIP caps, kanban, and CONWIP.

Go Deeper
WIP / Little's Law Calculator→Little's Law guide→
Related Terms
WIP
Inventory that has entered production but is not yet finished — the lever that controls lead time via Little's Law.
Throughput
The rate at which a system produces finished, sellable output — ultimately limited by the bottleneck.
Lead Time
The total elapsed time from order (or raw material) to delivery (or finished product), including all waiting.
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.
Capacity Utilization
Actual output as a percentage of maximum possible output — high utilization sounds good but drives up queue time.

Put Little's Law into practice

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