Lean Manufacturing & Operations worked example
Queue Time Estimate with units waiting in queue ahead of 30 units: a worked example
This scenario runs the queue time estimate calculation on the strong side: units waiting in queue ahead of 30 units, with every other input held at its documented default. Use this calculator to estimate how long a unit waits before processing at a given station, helping identify where lead time is consumed by waiting rather than processing.
The inputs for this scenario
- Units waiting in queue ahead: 30 units (raised for this scenario; the documented default is 12)
- Station cycle time per unit: 3 min (unchanged)
- Queue variability factor: 1.2 x (unchanged)
Working through the calculation
- Applying the documented formula (Queue Time = Units in Queue x Station Cycle Time x Variability Factor) to the inputs above produces each figure below.
- At this operating point the engine returns 108 min for estimated queue time, the number this scenario is built around.
- At this operating point the engine returns 108 value for base product.
- At this operating point the engine returns 1 x for multiplier.
- At this operating point the engine returns 90 value for factor a x b.
How this compares with the baseline
- Against the tool's baseline example, where units waiting in queue ahead sits at 12 units and the headline result is 43.2 min, this scenario comes in 150% above the baseline at 108 min.
- Use it during value-stream mapping or WIP analysis to quantify non-value-added wait at a specific buffer or workstation. Treat this as a target state: the delta against the baseline quantifies what the improvement is worth before you commit to chasing it.
Results at a glance
- Estimated queue time: 108 min (headline result)
- Base product: 108 value
- Multiplier: 1 x
- Factor A x B: 90 value
Run it with your numbers
- Every input above is editable in the live Queue Time Estimate calculator, which recalculates instantly and can be shared with the inputs intact.
Last reviewed 2026-05-12.