What is a WIP limit?
A WIP (work-in-progress) limit is a cap on the number of work items allowed in a workflow stage at any given time. When a column on a kanban board reaches its WIP limit, no new cards can enter until an existing card moves forward. This constraint is the single most impactful practice in kanban, and it is also the one most teams skip.
WIP limits work because they force teams to finish work before starting new work. Without them, the In Progress column becomes a graveyard of half-started tasks. People begin new items because starting feels productive, but it is finishing that delivers value. WIP limits make the cost of multitasking structurally impossible to ignore.
Why WIP limits improve delivery
Limiting work in progress produces three measurable effects. First, cycle time decreases because each task gets more focused attention instead of competing with a dozen other open items. Second, bottlenecks become visible immediately. When a column is at its WIP limit and work is queuing behind it, the constraint is obvious to the entire team. Third, quality improves because people are not context-switching between five tasks and making mistakes in all of them.
The relationship between WIP and cycle time is described by Little's Law: average cycle time equals work in progress divided by throughput. Reducing WIP while maintaining throughput directly reduces how long each item takes to complete. Teams that adopt WIP limits typically see cycle times drop by 30 to 50 percent within the first few weeks.
How to set WIP limits
Start with a WIP limit equal to the number of people working in that column. If you have four engineers, set the In Progress limit to four. Run with that for two weeks and observe. If cards still pile up, lower the limit. If people are frequently idle because the column is full, raise it. The goal is a steady pull-through where cards flow at a consistent pace without stalling.
Apply WIP limits to the Review column as well. A common pattern is setting Review's limit to half the In Progress limit, which encourages the team to review each other's work before starting anything new. This keeps the feedback loop tight and prevents a review bottleneck from forming downstream.
How Flux handles WIP limits
Flux displays the card count for each column on the board, making it straightforward to monitor WIP against your team's agreed limits. The board's real-time sync ensures that every team member sees the current count within seconds of any change. Combined with labels for priority and the activity log for tracking how cards flow through columns, teams can monitor and tune their WIP limits based on actual delivery data rather than guesswork.
Related terms
See also: Kanban, Cycle Time, Throughput.