Lean teams use kanban to stop overproduction and expose bottlenecks. Limiting work in progress shortens lead time and makes flow problems visible.
Where it comes from
Kanban was developed at Toyota under Taiichi Ohno as part of just-in-time production, inspired by how supermarkets restock shelves. It was later adapted for software and knowledge work.
At a glance
The two-bin kanban loop
Swipe sideways to see the whole diagram.
How to apply Kanban
- 1
Map the workflow
List the real steps work passes through, from request to done. Turn each step into a column or a stocking point.
- 2
Make work visible
Represent every item with a card, bin or ticket. Include blocked and waiting work, not only active tasks.
- 3
Set WIP limits
Cap how many items each step can hold. In production, size the number of kanban cards to demand and replenishment time.
- 4
Pull, don't push
Start new work only when a downstream signal or free capacity calls for it. Finish items before starting more.
- 5
Measure flow
Track lead time, throughput and work in progress. A cumulative flow diagram shows where work piles up.
- 6
Improve continuously
Review the board regularly and adjust limits and policies. Treat recurring blockers as kaizen opportunities.
Worked example (illustrative)
An assembly cell uses about 600 bolts a day and the stockroom refills within half a day. Each station keeps two bins of 200, so one bin covers the refill time with room to spare. When a bin empties, its card goes to the stockroom and the second bin keeps the station running. Over a month, stockouts fall from 6 to 0 and line-side stock drops by about a third, without a central schedule.
Common mistakes
- Building a board without WIP limits, which turns kanban into a to-do list.
- Setting card counts or limits once and never revisiting them as demand changes.
- Hiding blocked or unplanned work off the board, so flow metrics look better than reality.
When Kanban is not the right tool
Kanban suits repeating demand, where the same parts or types of work flow again and again. One-off, highly variable work is harder to run on fixed loops.
It also needs reasonably stable processes. Long breakdowns or changeovers drain the loop, so TPM and SMED often come first.
What is kanban?
Kanban is a pull system that uses visual signals to control how much work enters a process. In Japanese the word means signboard or card. In a factory, a kanban card tells the previous step to make or move only what was just used.
In office and software work, kanban usually means a board of cards with a limit on how much work can be in progress at once. The aim is the same in both cases: start less, finish more, and see where work is stuck.
Anatomy of a kanban board
A kanban board has columns for the stages of the work, such as To do, Doing and Done. Each piece of work is a card that moves from left to right. Each column can carry a work-in-progress (WIP) limit, written at the top.
Many boards add swimlanes for different classes of work, a column split into Doing and Ready for the next step, and a blocked marker on cards that are waiting. When a column reaches its WIP limit, the team finishes work before pulling more.
Kanban board examples
A support team might use Inbox, Triage, In progress, Waiting on customer and Resolved. A maintenance team might use Reported, Planned, Parts ready, In work and Closed. A production cell might use physical cards that circulate between a supermarket and the line.
For a simple template, start with three columns and one WIP limit on the middle column. Add columns only when the team can name a real handoff. Board tools are compared on the kanban software page. For the principles and practices behind the board, read the kanban methodology guide.
Toyota kanban and the Kanban Method
In the Toyota Production System, kanban are signal cards that authorize production or the movement of parts. Taiichi Ohno described the system in his book on TPS.
The Kanban Method for knowledge work, associated with David J. Anderson, adapts the idea to boards and WIP limits. The kanban software and e-kanban categories cover each use.
How many kanban cards? A worked count
This example is illustrative. A common formula is: cards = daily demand × replenishment time × (1 + safety factor) ÷ container size.
The cell uses 600 bolts a day, the refill takes 0.5 days, the team adds a 20% safety factor and each bin holds 200. That gives 600 × 0.5 × 1.2 ÷ 200 = 1.8, which rounds up to 2 cards.
Revisit the count when demand or refill time changes. If demand rises to 1,000 a day, the same formula gives 3 cards. The kanban calculator runs this for your own numbers.
Kanban board vs a to-do list
A kanban board can look like a to-do list on a wall. The difference is that a list tracks tasks, while a kanban board manages how the work flows.
| Compared | To-do list | Kanban board |
|---|---|---|
| What it shows | What needs doing | Where each item is in the process |
| Capacity | No limit, the list just grows | WIP limits stop the team taking on too much |
| Ownership | Often unclear | Each card shows its owner and any blocker |
| Priority | The order of the list, or whoever asks loudest | Agreed rules, readiness and classes of service |
| Improvement | Nothing built in | Flow metrics and regular reviews |
A list is fine for one person's errands. A board earns its place when work has several steps, several people or repeat bottlenecks.
Questions for the daily board review
A short daily meeting at the board keeps work moving. Walk the board from right to left and ask:
What is blocked?
Start here, since a blocked item ages fastest.
Which column is full?
That is today's bottleneck. Help there before starting anything new.
What is closest to done?
Finishing it frees capacity soonest.
Which items are getting old?
Compare each item's age with your usual cycle time.
Are we starting faster than we finish?
If the in-progress columns keep growing, stop starting.
Signs your kanban board is working
A healthy board makes work easier to see and easier to improve. It should cut confusion, not add admin. After a month, look for these signs:
- Status at a glance: anyone can say what is in progress and what is blocked without asking around.
- Finishing over starting: fewer items sit half done, and items finish more often.
- Earlier warnings: bottlenecks show up on the board before customers notice them.
- Clear handoffs: each card has an owner, and work does not get lost between people.
- Decisions at the board: the team uses it to choose what to do next, not only to report status.
If the board has become a chore to update, simplify it: fewer columns, fewer fields, one meeting.
| Kind | What it signals | Where you see it |
|---|---|---|
| Withdrawal kanban | Move parts from a store to the user | Between a supermarket and a line |
| Production kanban | Make parts to replace what was taken | At the supplying process |
| Signal kanban | Start a batch when stock hits a point | Batch processes such as presses |
| Board kanban | Start new work when WIP allows | Knowledge-work teams |
Guides on this topic
- Free kanban software: options, limits and when to payFree kanban software options, from a whiteboard or spreadsheet to free app plans and open-source tools. See what each option limits and how to choose.Read the guide
- Kanban board template: 6 layouts with columns and WIP limitsA kanban board template gives you columns, WIP limits, swimlanes and card fields. Copy six layouts, from simple three-column to service desk, and adapt them.Read the guide
- Kanban board examples: 15 boards from different settingsKanban board examples for factories, hospitals, offices, software, sales, support, portfolios, classrooms and homes, with columns, WIP limits and lessons.Read the guide
- Kanban project management: principles, practices and metricsKanban project management uses a visual board, WIP limits and flow metrics. Learn Anderson's principles and practices, and how kanban compares with Scrum.Read the guide
Sources
Books and papers show their publication year. Web pages show the month we last checked them.
- 1.Taiichi Ohno, Toyota Production System: Beyond Large-Scale Production (Productivity Press, 1988)
- 2.David J. Anderson, Kanban: Successful Evolutionary Change for Your Technology Business (Blue Hole Press, 2010)
- 3.John Coleman and Daniel Vacanti, The Kanban Guide (kanbanguides.org, May 2025 edition, checked October 2026)
- 4.John D. C. Little, A Proof for the Queuing Formula: L = λW (Operations Research 9(3), 1961)
- 5.Daniel S. Vacanti, Actionable Agile Metrics for Predictability (ActionableAgile Press, 2015)
- 6.Donald G. Reinertsen, The Principles of Product Development Flow (Celeritas Publishing, 2009)