WIP & Little's Law Calculator
See how much work in process your line is carrying from just two numbers: throughput and flow time. Your numbers stay in your browser.
Average work in process
0 units
How this is calculated
Little's Law is the core relationship of flow. For a stable process, the average amount of work in process equals the average throughput multiplied by the average time a unit spends in the system.
The same law rearranges to describe flow time from a known WIP and throughput:
Reading it well
- Keep units consistent. If throughput is units per hour, flow time must be in hours, so WIP comes out in units. Mixing hours and days or minutes will give a wrong answer.
- Averages, not snapshots. Little's Law describes long-run averages for a stable system, not a single moment when the line just started or just stopped.
- Less WIP, shorter flow time. At a fixed throughput, cutting WIP directly cuts flow time, which is the whole point of pull and one-piece flow.
To see how flow time and value-added time relate, try the process cycle efficiency calculator and the manufacturing lead time calculator, or read the lean manufacturing guide.
Make flow visible on your floor
Harmony connects your machines, systems, and paperwork into one real-time operational layer, no rip-and-replace, so WIP and flow time stop being estimates and become live signals. Read the CLS case study.
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