Conveyors calculator
Little's Law WIP Calculator for Conveyor Lines
Use this calculator when a line's WIP should be checked against throughput and lead time. It gives a practical Little's Law-style estimate for conveyorized production where WIP, flow rate, and elapsed time must stay aligned.
What this calculator does
- Estimate WIP from throughput, lead-time periods, uptime, and usable yield using a Little's Law-style relationship.
- an industrial engineer needs to check whether observed WIP matches line throughput and lead time
- The result estimates WIP implied by throughput and lead time for a conveyorized line.
Formula used
- Gross Little's Law WIP = throughput rate × lead time
- Usable WIP = gross WIP × uptime factor × usable yield
Inputs explained
- Line throughput rate: Use the average output rate in the same time period as the lead-time input.
- Average line lead time: Use elapsed time through the line expressed in the same period basis.
- Flow uptime factor: Reduce for blocked or starved flow that interrupts steady throughput.
- Usable WIP yield: Use the percent of WIP expected to remain usable or saleable.
How to use the result
- Use it when observed WIP seems too high or when lead-time reduction targets need a WIP target.
- Little's Law assumes stable averages; it is less reliable during startups, changeovers, campaigns, or highly variable queues.
Common questions
- What is Little's Law WIP for Conveyor Lines for? Estimate WIP from throughput, lead-time periods, uptime, and usable yield using a Little's Law-style relationship.
- What information do I need before using it? You need line throughput, average lead time on the same time basis, flow uptime, and usable WIP yield.
- When is the result only an estimate? The result is only a planning estimate when throughput and lead time are not stable over the measurement window.
- How can I use the result on the line? Use the WIP estimate to set FIFO limits, reduce queue length, or validate lead-time improvement targets.
Last reviewed 2026-05-12.