Cycle Time Throughput Calculator
Little's Law is the simple, powerful relationship behind every flow metric: the average work in progress equals the average throughput multiplied by the average cycle time. This calculator lets you pick which of the three you want to find, enter the other two, and solve for the third. It is ideal for Lean and Kanban teams diagnosing why delivery is slow, forecasting how long a queue will take to clear, or seeing how limiting work in progress shortens cycle time. Use consistent time units throughout, and average your figures over a representative, stable period.
Little's Law formula
WIP = throughput * cycle time
Throughput = WIP / cycle time
Cycle time = WIP / throughput
The calculator uses whichever rearrangement matches your chosen quantity, taking the two values you supply. Keep the time unit consistent: if throughput is items per week, cycle time must be in weeks. The relationship holds on average for a stable system.
Improving flow with Little's Law
- To deliver faster, reduce work in progress or raise throughput; the law links the two.
- Limiting work in progress is often the simplest lever and directly shortens cycle time.
- Average your inputs over a representative period rather than a single volatile day.
- Use the same time unit for throughput and cycle time, or the result will be wrong.
- Forecast queue clearance by dividing the backlog count by your measured throughput.
Cycle time and throughput: frequently asked questions
What is Little's Law?
Little's Law states that the average work in progress in a stable system equals the average throughput multiplied by the average cycle time: WIP = throughput x cycle time. It is a foundational result in queueing theory and underpins flow metrics in Lean and Kanban. Knowing any two of the three quantities lets you solve for the third.
What is the difference between cycle time and throughput?
Cycle time is how long one item takes to move through the process, from start to finish. Throughput is how many items the process completes per unit of time. They are related through Little's Law: for a given amount of work in progress, shorter cycle times allow higher throughput, and vice versa.
Which value does this calculator solve for?
Choose what you want to find: throughput, cycle time, or work in progress. Enter the other two values and the calculator applies Little's Law to compute the third. All inputs are user-editable so you can model your own process using whatever consistent time unit you measure in, such as days or weeks.
Does Little's Law require a stable system?
Yes. The law holds on average over a period in which the system is roughly stable, meaning arrivals and departures are balanced and the work in progress is not trending sharply up or down. Over short, volatile windows the instantaneous numbers can diverge, so use averages across a representative period.
How can I use this to improve flow?
Little's Law shows that to deliver faster you can either reduce work in progress or increase throughput. Limiting work in progress is often the most direct lever: with fewer items being worked at once, each finishes sooner, which lowers cycle time and makes delivery more predictable.
Official sources
- U.S. Bureau of Labor Statistics: Productivity concepts and measures.
- Scaled Agile Framework: Flow metrics and Little's Law.
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.