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Calculators / Business / Little’s law work in progress
Little’s law work in progress calculator
Estimate average work in progress from average throughput and average flow time.
On this page
Average work in progress30units
Calculator controls
How to calculate
Estimate average work in progress from average throughput and average flow time.
Average work in progress =
rate*time unitsWorked example
- Average throughput (units/h): 12
- Average flow time (h): 2.5
- Average work in progress: 30 units
Assumptions and limits
Applies to a stable system with consistent boundaries and long-run averages. This is not a prediction for an individual order or a rapidly changing backlog.
Results are rounded for display; calculations use unrounded values. Read our calculation methodology.
Understanding the result
Estimate average work in progress from average throughput and average flow time. Use completed throughput and total time inside the same system. Waiting and processing time both belong in the flow-time measure.
When this tool is useful
Use completed throughput and total time inside the same system. Waiting and processing time both belong in the flow-time measure.
Understanding your inputs
| Input | Example |
|---|---|
Average throughput (units/h) rate | 12 |
Average flow time (h) time | 2.5 |
Frequently asked questions
What does this model leave out?
Applies to a stable system with consistent boundaries and long-run averages. This is not a prediction for an individual order or a rapidly changing backlog.
How do I reproduce the example?
Enter the displayed example values in their labelled units. Apply the formula before rounding; change one input at a time to compare scenarios.