Kanban Work-in-Progress Limit Calculator
Estimate a starting WIP limit using throughput and target lead time, then add an explicit buffer for the scenario you want to evaluate.
How to use this calculator
- Enter average completed items per day, target lead time (days), buffer percentage; check the units and use values from the same period or scenario.
- Review the result and intermediate values; change one input at a time when comparing scenarios.
- Keep the stated formula and assumptions with any result you share.
Formula and method
Base WIP ≈ throughput per day × target lead time in days. Suggested WIP = ceiling(base WIP × (1 + buffer percentage ÷ 100)).
- Base WIP is 45 items; the buffered starting limit is 52 items.
- This is a planning heuristic, not a universal Kanban rule. Review service classes, variability, team structure and work-item sizes.
Worked examples
Worked example
18 completed items per day and 2.5 days of target lead time with a 15% buffer.
Base WIP is 45 items; the buffered starting limit is 52 items.
Base WIP is 45 items; the buffered starting limit is 52 items.
Understanding the result
Base WIP is 45 items; the buffered starting limit is 52 items.
This is a planning heuristic, not a universal Kanban rule. Review service classes, variability, team structure and work-item sizes.
Important notes
This is a planning heuristic, not a universal Kanban rule. Review service classes, variability, team structure and work-item sizes.
Use measured inputs and verify that the model matches the situation before making an operational, financial or technical decision.
Frequently asked questions
Should I set the limit exactly to this result?
Treat it as a hypothesis to validate from your workflow data.
Why include a buffer?
A buffer can accommodate variation, but a large buffer may also allow queues to grow.
What should I check before relying on this result?
Verify units, input definitions and assumptions against your real data or the relevant product, service or professional guidance.
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Related explanations
Learn the method behind the number or compare the terminology before using the calculator.
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This page provides a calculation tool plus explanatory information so you can understand what the result means and when the underlying method may not fit your situation.