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Delivery metrics · Free browser tool

Free Little's Law Calculator

Estimate average cycle time from average work in progress and average throughput in a stable workflow.

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What does this calculator do?

Little's Law relates average work in progress, average throughput and average time in a defined system. Use comparable averages, not unrelated snapshots.

Calculate your result

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Average active items during a representative period.

Throughput over the same workflow boundary and period.

Your entries stay in this browser session. Download or copy anything you want to keep.

Formula or structure

Average cycle time ≈ average WIP / average throughput

Method reference: John D. C. Little: A Proof for the Queuing Formula

Worked example

Average WIP of 12 items and throughput of 3 items per day imply approximately 4 days of average cycle time.

How to use it

  1. Read the field descriptions and use one consistent set of units.
  2. Enter your own figures or select Load example to inspect a worked scenario.
  3. Review the result alongside the assumptions below.
  4. Copy or download the output, then assign the next action in your planning workflow.

Assumptions and interpretation

The relationship concerns long-run averages in a stable system. An instantaneous board snapshot or a changing queue is not a dependable delivery forecast.

Read the practical guide

Questions about this tool

How does the little's law calculator work?
Little's Law relates average work in progress, average throughput and average time in a defined system. Use comparable averages, not unrelated snapshots.
Do I need an account to use this tool?
No. This tool is free to use in your browser without signing in. My First Task is optional if you want to manage the resulting work in a shared workspace.
Are my inputs uploaded or saved?
The tool processes inputs locally in the browser and does not upload them or store them in an account. Copy or download any results you want to keep before leaving the page.

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