Lean manufacturing

Little's Law Calculator

Little's Law states: WIP = Throughput × Lead Time. Given any two variables, solve for the third. Essential for understanding the relationship between inventory, flow rate, and lead time.

L = λW — where L is the average number of items in the system (WIP), λ (lambda) is the average throughput rate, and W is the average time an item spends in the system (lead time). The law holds for any stable system in steady state.

Solve for:

Result

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What-if scenarios

How does the result change as you vary the inputs?

Interpretation guide

To reduce lead time: reduce WIP or increase throughput rate.

To increase throughput: reduce WIP or reduce lead time.

Practical use: If you cap your WIP (a kanban limit), Little's Law tells you exactly what lead time to promise customers at your current throughput rate.