Lean Manufacturing & Operations worked example

WIP Days of Supply with current wip level of 100 units: a worked example

Here is what the math looks like when conditions slip. We hold every other input steady and drop current wip level to 100 units, then walk the calculation through step by step. Calculate how many days of production your current WIP level represents by dividing WIP by daily throughput.

The inputs for this scenario

  • Current WIP level: 100 units (the input this scenario stresses; the baseline uses 200)
  • Daily throughput: 50 units/day (held at the documented default)
  • Unit conversion factor: 1 x (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: WIP Days = Current WIP / Daily Throughput x Conversion Factor.
  • WIP days of supply works out to 2 days at these inputs, and this is the headline figure for the scenario.
  • Raw ratio works out to 2 value at these inputs.
  • Conversion factor works out to 1 x at these inputs.
  • Daily throughput works out to 50 value at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where current wip level sits at 200 units and the headline result is 4 days, this scenario comes in 50% below the baseline at 2 days.
  • The practical read: the gap between this scenario and the baseline is entirely attributable to current wip level, so recovering it is worth quantifying in dollars before considering equipment or staffing changes. It assumes daily throughput is steady; on a line with high day-to-day variation or seasonal demand, a single throughput figure can over- or under-state the true days of supply.

Results at a glance

  • WIP days of supply: 2 days (headline result)
  • Raw ratio: 2 value
  • Conversion factor: 1 x
  • Daily throughput: 50 value

Run it with your numbers

  • To rerun this with your own numbers, open the live WIP Days of Supply calculator, set current wip level to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.