Conveyors worked example

Little's Law WIP for Conveyor Lines at 66% flow uptime factor: a worked example

This worked example runs the little's law wip for conveyor lines numbers for a tougher week than the baseline: 66% flow uptime factor instead of the typical 92%. Estimate WIP from throughput, lead-time periods, uptime, and usable yield using a Little's Law-style relationship.

The inputs for this scenario

  • Line throughput rate: 520 units / period (held at the documented default)
  • Average line lead time: 1.8 periods (held at the documented default)
  • Flow uptime factor: 66 % (the input this scenario stresses; the baseline uses 92)
  • Usable WIP yield: 99 % (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Gross Little's Law WIP = throughput rate × lead time.
  • Estimated line WIP works out to 612 WIP units at these inputs, and this is the headline figure for the scenario.
  • Gross Little's Law WIP works out to 936 WIP units at these inputs.
  • WIP impact from flow downtime works out to 318 WIP units at these inputs.
  • WIP impact from unusable units works out to 6.18 WIP units at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where flow uptime factor sits at 92% and the headline result is 853 WIP units, this scenario comes in 28.26% below the baseline at 612 WIP units.
  • Use it to size or sanity-check WIP on a flow or conveyor line when you know the production rate and average dwell time. A result at this level usually justifies acting on the stressed input before touching anything else, because every other figure in the table is downstream of it.

Results at a glance

  • Estimated line WIP: 612 WIP units (headline result)
  • Gross Little's Law WIP: 936 WIP units
  • WIP impact from flow downtime: 318 WIP units
  • WIP impact from unusable units: 6.18 WIP units

Run it with your numbers

  • To rerun this with your own numbers, open the live Little's Law WIP for Conveyor Lines calculator, set flow uptime factor to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.